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Thermophilic bacteria able to produce exopolysaccharides (EPSs) have become attractive in recent years. EPSs synthesized by thermophiles are worth investigating due to their unexplored structural and biological properties. In this study, EPSs from thermophilic, Gram-positive bacterial isolates were purified and tested for their biological activities. A total of one hundred seven thermophilic bacteria were screened for their ability to produce exopolysaccharides. Nine isolates belonging to Geobacillus, Parageobacillus, Aeribacillus, and Anoxybacillus genera with highest EPS production were chosen, and purified EPSs (20, 61, 74, 76, 78, 89, 106, 134, and 261) were used for biological activity studies. EPS yields of selected thermophilic bacteria ranged between 117 and 419 mg/L. Among the tested EPSs, 61, 106, and 261 showed antibacterial effect against E. faecalis JH2-2 at a final concentration of 1.5 mg/mL. EPS samples had significant antioxidant capacity, especially EPS 134, with the highest DPPH radical scavenging activity of 100% at a concentration of 5 mg/mL and the strongest reducing power. EPS 20 showed the highest lipid peroxidation inhibition effect at a rate of 31%. EPSs displayed weak alpha-amylase inhibition activity when compared with standard acarbose. The prebiotic indices of EPSs 20, 61, 76, 89, 134, and 261 were found to be higher than that of inulin, a representative prebiotic carbohydrate for all tested lactic acid bacteria in the study. All examined EPSs inhibited the biofilms formed by various bacteria depending on the test strain. Results indicated that thermophilic EPSs had remarkable antioxidant, prebiotic, and antibiofilm activities. Therefore, EPSs characterized in this study may have technological applications in health and food fields., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Numerous metagenomics studies, conducted in both full-scale anaerobic digesters and household biogas plants, have shed light on the composition and activity of microbial flora essential for optimizing the performance of biogas reactors, underscoring the significance of microbial community composition in biogas plant efficiency. Although the efficiency of household biogas plants in the sub-Himalayan region has been reported, there is no literature evidence on the microbial community structure of such household biogas plants in the sub-Himalayan region. The current study evaluated the physico-chemical properties and bacterial community structure from the slurry samples of household biogas plants prevalent in the sub-Himalayan region. The slurry samples were observed to be rich in nutrients; however, their carbon and nitrogen contents were higher than the recommended standard values of liquid-fermented organic manure. The species richness and diversity indices (Chao1, Shannon, and Simpson) of household biogas plants were quite similar to the advanced biogas reactors operating at mesophilic conditions. 16S rRNA gene amplicon sequencing reveals microbial diversity, showing a higher abundance of Firmicutes (70.9%) and Euryarchaeota (9.52%) in advanced biogas reactors compared to household biogas plants. Microbial analysis shows a lack of beneficial microbes for anaerobic digestion, which might be the reason for inefficient biogas production in household biogas plants of the sub-Himalayan region. The lack of efficient bacterial biomass may also be attributed to the digester design, feedstock, and ambient temperatures. This study emphasized the establishment of efficient microbial consortia for enhanced degradation rates that may increase the methane yield in biogas plants., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Isolated axenic culture of Acutodesmus obliquus was identified using 28S DNA-based molecular method from the Vastral lake of Gujarat, India. In present study, newly isolated species A.obliquus used for the treatment of CETP-WW and CO2 sequestration. Direct relation was observed in between pollution load and nutrient load of CETP wastewater with biochemical profile of A. obliquus was obliquus. The COD/BOD ratio (1.9) was found to be significant on the scale of degradability by algal biomass. Reduction in BOD and COD was obtained maximum in order with 25 > 50 > 75 > 100% of CETP wastewater etc.; 82.3%, 71.9%, 52.2%, and 48.4% for BOD; and 75.4%, 68.5%, 53.9%, and 46.5% for COD. Findings showed that CETP-WW wastewater is rich in nutrients, which can be utilized for algal biomass production. A. obliquus was subjected to four different concentrations (5%, 10%, 15%, and 20%) of carbon (gaseous form) in 50% concentration of CETP-WW. Maximum biomass productivity was obtained (2.09 ± 0.08 gL−1) with 10% CO2 supply. The correlation was observed in all the concentrations 25%, 50%, 75%, and 100% of CETP-WW of BOD, COD, NO3−, and PO4−3 between the protein, carbohydrate, and lipid. It indicated that microalgae have the potential to simultaneously realize CETP-WW wastewater purification and CO2 fixation with value-added ingredients co-production. [ABSTRACT FROM AUTHOR]

Huge quantities of municipal solid waste and food chain supply waste are unfavourable outcomes of rapid population growth and urbanization. Organic municipal waste majorly consists of decomposable, recyclable, and inert waste and contributes to 57% of municipal waste generated globally. Fruits and vegetables wastes are major component of organic municipal waste, and contains significant amount of carbohydrates, proteins, fats, minerals and fibres that can be valorised through various innovative and sustainable strategies. One of the most important approaches is leveraging the catalytic capabilities of microbial enzymes to convert complex organic compounds to varied valuable products like, essential oils, bio-oil, ethanol, biogas, phenolics, flavonoids, anthocyanin, dietary products etc. Development of environment friendly sustainable processes also handles the challenges associated with waste disposal and boost nation's financial status through circular bioeconomy. The present review focusses on details of major organic municipal waste, with specific emphasis on fruit and vegetable remains, their composition, management and value-added products obtained from these resources. It also gives a detailed account on green technology approach of waste valorisation through microbial enzymes, recent technological interventions involved in the process and discusses the future market potential and growth prospects in the studied area. [ABSTRACT FROM AUTHOR]

This review explores the potential of green synthesised SBA-15 nanomaterials in biodiesel production, focusing on their promising application despite their lack of direct use in this field. The growing global demand for sustainable and renewable energy sources has intensified interest in biodiesel as a cleaner alternative to fossil fuels. Biodiesel, derived from renewable biomass sources such as agricultural residues and waste cooking oils, offers significant environmental benefits, including reduced greenhouse gas emissions. Traditional SBA-15 synthesis involves hazardous chemicals, but green synthesis methods using biomass-derived silica present an eco-friendly approach. This review examines the unique structural properties of SBA-15, such as its high surface area and uniform pore structure, which could improve biodiesel production when used as a catalyst. While the green-synthesised SBA-15 has not yet been applied directly in biodiesel production, this article proposes its potential utility and emphasises the need for future research to validate its effectiveness. This novel approach of directly using SBA-15 as a catalyst emphasises its potential to improve biodiesel production sustainability and efficiency, contributing to waste management and renewable energy goals. These findings underscore the scientific value of SBA-15 in the advancement of biofuel technology and highlight its potential for industrial applications.Article Highlights: Examines biomass waste as a viable and renewable resource for silica extraction. Evaluates green synthesis approaches for producing SBA-15 from renewable sources. Consider the prospective use of green-synthesised SBA-15 in the advancement of biodiesel production technologies. [ABSTRACT FROM AUTHOR]

The study presented a comprehensive documentation of different operating parameters influencing bioelectricity generation potential of PMFCs with Chlorella sorokiniana-based microalgal bio-cathode. An optimum duration of light-dark period is highly essential for growth of both plants and microalgae. The study demonstrated that 12/12 h light-dark phase was optimum to extract maximum performance from PMFCs without creating operational stress. The effect of different light sources on growth of indoor plants Philodendron erubescens and Epipremnum aureum as well as microalgae was studied. White light proved to be superior among all light source for plant growth and chlorophyll concentration at the bio-cathode. The obtained power density of 26.42 mW m−2 under white light was 72%, 54% and 15% higher than red, blue and red-blue mix lights, respectively. Also, the addition of novel plant growth media can influence plant growth resulting in 31% increased power generation. The configuration of PMFC setup and placement of electrodes and membranes are highly important criteria affecting PMFC performance. Anode position at A2 at 7 cm below soil, being closer to membranes proved to enhance transmembrane ion transport with an increase in power density up to 2.2 times. Three-chamber PMFC with narrow bottom anode chamber helps in creating favourable anaerobic environment with 26% decrease in O2 concentration and increasing power generation up to 31.40 mW m−2 which was 15.44% higher as compared to two-chamber PMFC. Additionally, the internal resistance was found to decrease from 270 to 190 Ω. [ABSTRACT FROM AUTHOR]

Microalgae-based biocathode development was studied for the first time in a three-chamber PMFC incorporating Chlorella sorokiniana. It represents an efficient, cost-effective and eco-friendly strategy for increase oxygen availability to the cathode. Three different indoor plants viz., Epipremnum aureum, Philodendron erubescens and Anthurium andreanum were chosen for this study. Among all the PMFCs, P. erubescens showed the highest performance, with the power density and current density of 32.21 mW m−2 and 63 mA m−2 respectively. This represents a 31% increase with respect to previous studied bacterial biocathode and is amongst the best in PMFC research reported till date. Cyclic voltammetry (CV), dissolved oxygen (DO) and Field emission scanning electron microscopy (FESEM) analysis confirmed microalgal biocathode development. The presence of C. sorokiniana in the cathode increases the DO concentration and the oxygen reduction rate with a higher reduction current density of −16.2 mA m−2 as compared to mechanical aeration (−5.6 mA m−2). Anodic microbial community structure showed a diverse bacterial consortium dominated by Firmicutes (56.84%) and Bacteroidetes (38.45%), which are known for their ability to generate bioelectricity. [ABSTRACT FROM AUTHOR]

Lignocellulose revalorization has emerged as a major solution to mitigate the increasing energy demand of the growing population. Lignocellulosic biomass is considered the building block of plant cell walls and is mainly composed of cellulose, hemicellulose, and lignin. The biomass needs to be processed efficiently to produce value-added products and bioenergy. Therefore, this study aims to systematically review various conversion technologies, like thermal conversion, and biological pretreatments available to achieve this. The use of the biological pretreatment method is cost-effective and eco-friendly. Many microorganisms, different strains of bacteria, fungus, etc., are used here to exploit their cellulolytic and ligninolytic properties. It covers the life cycle assessment of lignocellulose pretreatment, downstream processing for conversion of lignocellulose to biofuel, and techno-economic analysis. The attention has also been given to the development of biorefineries to enhance the production efficiency of bioenergy from the lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

Bioethanol is a sustainable energy alternative and can contribute to global greenhouse-gas emission reductions by over 60%. Its industrial production faces various bottlenecks, including sub-optimal efficiency resulting from bacteria. Broad-spectrum removal of these contaminants results in negligible gains, suggesting that the process is shaped by ecological interactions within the microbial community. Here, we survey the microbiome across all process steps at two biorefineries, over three timepoints in a production season. Leveraging shotgun metagenomics and cultivation-based approaches, we identify beneficial bacteria and find improved outcome when yeast-to-bacteria ratios increase during fermentation. We provide a microbial gene catalogue which reveals bacteria-specific pathways associated with performance. We also show that Limosilactobacillus fermentum overgrowth lowers production, with one strain reducing yield by ~5% in laboratory fermentations, potentially due to its metabolite profile. Temperature is found to be a major driver for strain-level dynamics. Improved microbial management strategies could unlock environmental and economic gains in this US $ 60 billion industry enabling its wider adoption. Industrial bioethanol production is driven by ecological interactions within the microbial community rather than the interactions within yeast population. Here, the authors identify bacteria affecting ethanol production and reveal temperature as the major driving force for strain-level dynamics. [ABSTRACT FROM AUTHOR]

Agricultural residues are readily available and inexpensive renewable resources in China and can be utilized for reducing China's reliance on fossil fuels and CO2 emissions. This study conducted a systematic study of energy production and consumption, CO2 emissions, and agricultural residues available for energy and environmental benefits in China. The gap between the domestic production and consumption of energy in China was large. China's energy consumption structure was dominated by coal over the past thirty years, which was strongly linked the increasing CO2 emissions in China. China has abundant agricultural residues resource, most of which were utilized as soil amendments, animal feeds, substrates in mushroom cultivation, and industrial materials. The usable agricultural residues for energy were estimated to be about 226.9 million tons in 2020. If those usable agricultural residues would be converted into bio-oil and biochar through pyrolysis, it could not only replace about 102 million tons of crude oil, but also sequestrate about 209 million tons of CO2-equivalent. It is expected that the results from this study can promote the application of agricultural residues in potential of energy production and carbon sequestration. Statement of Novelty: In this study, the energy production and consumption, CO2 emissions, and pyrolysis conversion of agricultural residues resources for energy and environmental benefits in China were comprehensively investigated. The highlights are listed as follows: (1) Gap between energy production and consumption in China became larger and larger; (2) CO2 emissions has significantly increased by three times during the past three decades; (3) Total collectable agricultural residues annually reached 0.96 billion tons; (4) Usable agricultural residues for energy annually reached 227 million tons; (5) Pyrolysis of agricultural residues is effective for energy and environmental benefits. [ABSTRACT FROM AUTHOR]

Pines play a significant role in forest biodiversity globally and generate huge forest litter. Dry pine needles due to low ignition temperature and high frictional force with the ground catch fire quickly. Annual forest fires in the northern states of India greatly impact the Indian economy besides causing huge loss to biodiversity, livelihood, and environment. Pine needles are also considered unfit for fodder consumption due to presence of tannins. Although the presence of softwood lignin in pine needles makes it difficult to degrade easily, the presence of holocellulose (68.5%) containing 45–51% cellulose makes this biomass a potential substrate to be used in pulp-making industries for low-grade paper sheets. The good fiber length of pine needles (1.3–1.4 mm) with a diameter of 30–32 μm, maybe considered important property for paper making. The use of pine needles in the pharmaceutical and food industries are due to the presence of secondary metabolites (α-pinene, β-pinene, caryophyllene etc.). The various other potential applications of pine needles are for producing bio-ethanol (yield, 3.98%; purity, 94%), biogas (yield, 23.1 L kg−1), smokeless briquettes (calorific value, 18.77 MJ kg−1), biochar (calorific value, 25.6 MJ kg−1), bio-composites (tensile strength, 21–60 MPa), and bio-pesticides. This paper comprehensively reviews the current applications of pine needles along with its future prospective applications that can have the dual advantage of providing employment opportunities to the people along with environmental protection. [ABSTRACT FROM AUTHOR]

A novel xylanase gene (denominated xynDRTY1) was identified from Tengchong hot spring by a metagenomic approach. Its amino acid sequence was 73.43% identical to a hypothetical protein from Bryobacterales bacterium. The codon-optimized XynDRTY1 gene was synthesized and overexpressed in Escherichia coli. The XynDRTY1 was purified by using Ni–NTA affinity chromatography. It exhibited activity with natural glycosides, such as beechwood xylan (21.2 ± 3 U/mg) and oat spelt xylan (8.2 ± 0.3 U/mg). Its optimum pH was determined to be 6.0 and optimum temperature of 65 ℃, along with its stability over 140% and 110% relative enzyme activity after incubation at 60 ℃ for 20 min and 120 min, respectively. Based on these findings, we believe that XynDRTY1, as thermostable xylanase, may prove useful for biotechnological applications. [ABSTRACT FROM AUTHOR]

It was tested the production of a viscous exopolysaccharide (EPS) by Lelliottia amnigena using different concentrations (10, 15, 25, 50 and 100%) of produced water (PW) and Dialyzed PW (DPW) at 100% concentration, with a nutrient medium based on glycerin and sucrose as carbon sources in 44 h batches. There was an increase in EPS recovery when used PW up to a concentration of 25%. The viscosity of the EPS solutions was maintained with DPW and up to 15% of PW, such a condition resulted in 9.34 gL− 1 of EPS, representing an increase of 84.9% compared to the control (P < 0.0001). The PW 15% increased the viscosity per produced liter by 114.3% (P < 0.0001). Scanning electron microscopy and Energy-dispersive X-ray spectroscopy analysis showed that EPS adsorbed mineral constituents of the substrate and its characterization by Fourier Transform Infrared Spectroscopy was similar to an external control of a commercial EPS produced by an Enterobacter A47 strain. PW at 15% becomes an alternative to increase the EPS production process and can contribute to the mitigation of environmental damage through sustainable PW management in the oilfield chain. [ABSTRACT FROM AUTHOR]

An alternative to mitigate the environmental impact of food waste is the separation of valuable components. Due to the difficulty and heterogeneity of such wastes, the study of model systems allowing a regular and predictable production and composition was used. A mixture of pre- and post-consumption kitchen wastes from a hospital with an automated organic matter segregation and drying system (HKW) has been collected to obtain representative samples of the different diets prepared daily. The chemical characterization of streams revealed a variation in composition of the wastes depending on the menus. Those from dinner + breakfast (D + B) presented protein content in the range 42–54% of the dry weight and those form lunch + snack (L + S) in the range 19–33%, whereas the carbohydrate content was 52–65% in D + B and 47–53% in L + S waste streams. These values suggested the possibility of proposing a different valorization scheme for each type of stream. In this study, a green extraction process with pressurized hot water under microwave heating has been explored for the solubilization of the most abundant and valuable components, protein, and carbohydrates. The starch fractions recovered from the crude extract were proposed for the formulation of anti-freezing hydrogels suitable for 3D printing, and the possibilities of valorizing other fractions such as proteins as plant biostimulants are also discussed. [ABSTRACT FROM AUTHOR]

A type of high molecular weight bioactive polymers called exopolysaccharides (EPS) are produced by thermophiles, the extremophilic microbes that thrive in acidic environmental conditions of hot springs with excessively warm temperatures. Over time, EPS became important as natural biotechnological additives because of their noncytotoxic, emulsifying, antioxidant, or immunostimulant activities. In this article, we unravelled a new EPS produced by Staphylococcus sp. BSP3 from an acidic (pH 6.03) San Pedro hot spring (38.1 °C) located in the central Andean mountains in Chile. Several physicochemical techniques were performed to characterize the EPS structure including Scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), 1D Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). It was confirmed that the amorphous surface of the BSP3 EPS, composed of rough pillar-like nanostructures, is evenly distributed. The main EPS monosaccharide constituents were mannose (72%), glucose (24%) and galactose (4%). Also, it is a medium molecular weight (43.7 kDa) heteropolysaccharide. NMR spectroscopy demonstrated the presence of a [→ 6)-⍺-d-Manp-(1 → 6)-⍺-d-Manp-(1 →] backbone 2-O substituted with 1-⍺-d-Manp. A high thermal stability of EPS (287 °C) was confirmed by TGA analysis. Emulsification, antioxidant, flocculation, water-holding (WHC), and oil-holding (OHC) capacities are also studied for biotechnological industry applications. The results demonstrated that BSP3 EPS could be used as a biodegradable material for different purposes, like flocculation and natural additives in product formulation. [ABSTRACT FROM AUTHOR]

Rheinheimera sp. laccase was cloned and engineered to truncate domain 3 previously in our laboratory. This engineered laccase was found to deink old newsprint paper (ONP) without the need of any mediator. Response surface methodology (RSM) for statistical optimization of deinking conditions achieved deinking efficiency of 55.66% with enzyme dose of 130 U/g odp (oven-dried pulp), treatment time of 4 h and pulp consistency 5%, irrespective of the presence or absence of mediator (1-hydroxybenzotriazole; HBT). The optimized enzymatic pretreatment for deinking was validated in the R&D setup of Kuantum Papers Ltd., Hoshiarpur, Punjab (India), and an increase of 16.69, 17.18, 11.62 and 25% in brightness, breaking length, tear factor and burst factor, respectively, was achieved in addition to reducing the usage of hazardous chemicals by 50%. These results show the promising application of a greener enzymatic approach for environmentally sustainable paper recycling. [ABSTRACT FROM AUTHOR]

The endoxylanase XT6 produced by Geobacillus stearothermophilus is a desirable candidate for industrial applications. In this study, the gene encoding XT6 was cloned using the pET-28a expression vector and expressed in Escherichia coli BL21 (DE3) cells. Recombinant XT6 production was improved by optimizing cell lysis (sonication, chemical, and enzymatic lysis) and expression conditions. Sonication in a 0.05 M sodium phosphate (pH 6.0) buffer resulted in the highest xylanase activity (16.48 U/ml). Screening and optimization of induction conditions using the Plackett–Burman Design and Box-Behnken Design (BBD) approaches revealed that cell density pre-induction (OD600 nm), post-induction incubation time, and IPTG concentration significantly (p < 0.05) influenced the expression levels of XT6 (16.48 U/ml to 40.06 U/ml) representing a 3.60-fold increase. BBD resulted in a further 8.74-fold increase in activity to 144.02 U/ml. Batch fermentation in a 5-l stirred tank bioreactor at 1 vvm aeration boosted recombinant xylanase production levels to 165 U/ml suggesting that heterologous expression of the XT6 enzyme is suitable for scaled-up production. The pure enzyme with a molecular weight of 43 kDa and a 15.69-fold increase in purity was obtained using affinity chromatography and a cobalt column. Future studies will include application of the purified recombinant xylanase to animal feed. [ABSTRACT FROM AUTHOR]

Sulfate-reducing bacteria (SRB) are terminal members of any anaerobic food chain. For example, they critically influence the biogeochemical cycling of carbon, nitrogen, sulfur, and metals (natural environment) as well as the corrosion of civil infrastructure (built environment). The United States alone spends nearly $4 billion to address the biocorrosion challenges of SRB. It is important to analyze the genetic mechanisms of these organisms under environmental stresses. The current study uses complementary methodologies, viz., transcriptome-wide marker gene panel mapping and gene clustering analysis to decipher the stress mechanisms in four SRB. Here, the accessible RNA-sequencing data from the public domains were mined to identify the key transcriptional signatures. Crucial transcriptional candidate genes of Desulfovibrio spp. were accomplished and validated the gene cluster prediction. In addition, the unique transcriptional signatures of Oleidesulfovibrio alaskensis (OA-G20) at graphene and copper interfaces were discussed using in-house RNA-sequencing data. Furthermore, the comparative genomic analysis revealed 12,821 genes with translation, among which 10,178 genes were in homolog families and 2643 genes were in singleton families were observed among the 4 genomes studied. The current study paves a path for developing predictive deep learning tools for interpretable and mechanistic learning analysis of the SRB gene regulation. [ABSTRACT FROM AUTHOR]

A non-motile, novel actinobacterial strain, Kera-3T, which is a gram-positive, aerobic, rod-shaped bacterium, was isolated from human keratinocytes on 1/10 diluted R2A agar. Whole-cell hydrolysis of amino acids revealed the presence of meso-DAP, alanine, and glutamic acid. The predominant menaquinone was MK-9 (H8), whereas the primary fatty acids were C16:0 and C18:1ω9c. The major phospholipids included diphosphatidylglycerol and aminophospholipids, along with an unidentified phosphoglycolipid and an aminophosphoglycolipid. The G+C content of the genomic DNA was 73.2%, based on the complete genome sequence. Phylogenetic analyses of the 16S rRNA gene sequence and phylogenomic analysis of 91 core genes showed that strain Kera-3T formed a new lineage in the family Iamiaceae, with the closest neighbour Rhabdothermincola sediminis SYSU G02662T having 91.19% 16S rRNA gene sequence identity. A comparative genomic study of the predicted general metabolism and carbohydrate-active enzymes supported the phylogenetic and phylogenomic data. Based on the analysis of physiological, biochemical, and genomic characteristics, strain Kera-3T can be distinguished from known genera in the family Iamiaceae and represents a novel genus and species. Therefore, the name Dermatobacter hominis gen. nov., sp. nov. was proposed, with the type strain Kera-3T (= KACC 22415T = LMG 32493T). [ABSTRACT FROM AUTHOR]

This study aimed to production, optimization, and characterization of an exopolysaccharide (EPS) by Bacillus coagulans IBRC-M10807. The maximum EPS production (234.21 ± 4.83 mg/L) was obtained under optimal incubation temperature 54.95 °C, incubation time 31.36 h, initial pH 5.73, casein peptone concentration 3.93%, and lactose concentration 1.33%. The monosaccharide compositions of EPS were mannose, rhamnose, glucose, and galactose, with an average molecular weight of 4.22 × 105 Da. Differential scanning calorimetry and thermogravimetric analysis showed that the EPS had high thermal stability with a melting point of 262.5 °C and degradation temperature of 276.29 °C. DPPH radical scavenging, hydroxyl radical scavenging, and reducing power of EPS were 85.25% ± 0.55%, 80.08% ± 0.31%, and 0.824 ± 0.008 at 2 mg/mL concentration, respectively. These results indicated that the EPS produced by B. coagulans IBRC-M10807 could be a promising candidate for use as a safe and natural antioxidant as well as a functional ingredient in the pharmacy and food industry. [ABSTRACT FROM AUTHOR]

The properties of hexagonal boron nitride (hBN) were explored to improve the chemical and thermal performance of a three-dimensionally interconnected hBN (3Di-hBN)-reinforced Cu0.7–Ni0.3 (3Di-hBN CuNi) composite, prepared via a simple two-step process. The chemical performance was examined by potentiodynamic polarization and electrochemical impedance spectroscopy, whereas the thermal performance was investigated by thermogravimetric analysis and high-temperature oxidation experiments. The 3Di-hBN CuNi composite exhibited a corrosion resistance six times higher than that of a powder metallurgy (PM) CuNi alloy (without hBN). Furthermore, during high-temperature oxidation experiments at 900 °C, the 3Di-hBN CuNi composite gained ~ 36% less mass than the PM CuNi alloy, indicating its superior high-temperature oxidation resistance. The improved chemical and thermal stability of the 3Di-hBN CuNi composite were attributed to the impermeability and thermal stability of hBN, that is, its ability to obstruct the penetration and diffusion of atoms, ions, and molecules at high temperatures. [ABSTRACT FROM AUTHOR]

A new thermophilic strain, designated as Bacillus sp. LMB3902, was isolated from Hammam Debagh, the hottest spring in Algeria (up to 98 °C). This isolate showed high protease production in skim milk media at 55 °C and exhibited significant specific protease activity by using azocasein as a substrate (157.50 U/mg). Through conventional methods, chemotaxonomic characteristics, 16S rRNA gene sequencing, and comparative genomic analysis with the closely related strain Bacillus licheniformis DSM 13 (ATCC 14580  T ), the isolate Bacillus sp. LMB3902 was identified as a potentially new strain of Bacillus licheniformis. In addition, the gene functions of Bacillus sp. LMB3902 strain were predicted using the Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Clusters of Orthologous Groups, Non-Redundant Protein Sequence Database, Swiss-Prot, and Pfam databases. The results showed that the genome size of Bacillus sp. LMB3902 was 4.279.557 bp, with an average GC content of 46%. The genome contained 4.760 predicted genes, including 8 rRNAs, 78 tRNAs, and 24 sRNAs. A total of 235 protease genes were annotated including 50 proteases with transmembrane helix structures and eight secreted proteases with signal peptides. Additionally, the majority of secondary metabolites found by antiSMASH platform showed low similarity to identified natural products, such as fengicin (53%), lichenysin (57%), and surfactin (34%), suggesting that this strain may encode for novel uncharacterized natural products which can be useful for biotechnological applications. This study is the first report that describes the complete genome sequence, taxono-genomics, and gene annotation as well as protease production of the Bacillus genus in this hydrothermal vent., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The bio-cyanidation process of various cyanogenic microorganisms is found to be a sustainable and effective method for metals recovery from primary and secondary sources. This process has surpassed the limitations of the chemical cyanide treatment process; thus, prioritized as a promising approach for e-waste "urban mining" strategies. The main focus of the study was to enhance the bioleaching capacity of indigenous Bacillus sp. ISO1 and to implement optimized parameters in large-scale bioleaching operations. The assessment of various amino acids unveiled that like other cyanogenic microorganisms Bacillus sp. ISO1 also preferred glycine as a prime precursor for cyanide synthesis, as maximum metal solubilization was achieved with glycine amino acid. Other amino acids influenced the bacterial growth but not significantly affected the biocyanidation process. The evaluation and optimization of methionine as a lixiviant stimulator demonstrated that the addition of 1 mg/L methionine effectively enhance the production of glycine-utilizing cyanide lixiviant, that led to a significant solubilization of Cu (86%), Au (75%), and Ag (63%) metals. Furthermore, the kinetics of metal solubilization and operating conditions were explored at increased volume (i.e., 3 L working volume) of bioleaching medium to assess the industrial scale potential of this potent bacterial strain with optimized parameters such as temperature, pH, pulp density, and inoculum size. The significant recovery of Cu (˃ 60%) and other metals at this substantial volume suggested the implementation of a bioleaching process with this potent bacterial strain at industrial scale operations., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The expertise of synthetic organic chemistry accumulated over the past century has been instrumental in converting biomass to fuels, chemicals, and materials. Particular emphasis has been attributed to using eco-friendly reagents and reaction conditions by adhering to the principles of green chemistry. Catalysis remains at the heart of organic synthesis and has a ubiquitous presence in the organic chemistry literature. Not surprisingly, catalytic processes are increasingly used in the chemistry of renewables under commercially relevant and environmentally acceptable conditions. In this review, the synthesis of various biofuels and renewable chemicals from biomass-derived furfural and 5-(hydroxymethyl)furfural has been elaborated. Synthetic upgrading of furfurals has been shown in the light of chemical modifications of the reactive sites present in them. This review aims to provide a critical understanding of the influence of synthetic organic chemistry in biomass value addition via the furanic platform. This work will encourage the researchers to improve the existing synthetic pathways, develop new synthetic strategies, and broaden the scope of applications for biorenewable products. [ABSTRACT FROM AUTHOR]

Geobacillus sp. ID17 is a gram-positive thermophilic bacterium isolated from Deception Island, Antarctica, which has shown to exhibit remarkable laccase activity in crude extract at high temperatures. A bioinformatic search using local databases led to the identification of three putative multicopper oxidase sequences in the genome of this microorganism. Sequence analysis revealed that one of those sequences contains the four-essential copper-binding sites present in other well characterized laccases. The gene encoding this sequence was cloned and overexpressed in Escherichia coli, partially purified and preliminary biochemically characterized. The resulting recombinant enzyme was recovered in active and soluble form, exhibiting optimum copper-dependent laccase activity at 55 °C, pH 6.5 with syringaldazine substrate, retaining over 60% of its activity after 1 h at 55 and 60 °C. In addition, this thermophilic enzyme is not affected by common inhibitors SDS, NaCl and l-cysteine. Furthermore, biodecolorization assays revealed that this laccase is capable of degrading 60% of malachite green, 54% of Congo red, and 52% of Remazol Brilliant Blue R, after 6 h at 55 °C with aid of ABTS as redox mediator. The observed properties of this enzyme and the relatively straightforward overexpression and partial purification of it could be of great interest for future biotechnology applications. [ABSTRACT FROM AUTHOR]

Desizing and biodegradability are considered among the most important processes in the textile industry. Desizing removes the protective coating on the surface of yarn to ensure high efficiency and enhanced quality of subsequent stages such as bleaching, scouring, dyeing and printing, while good biodegradation ensures green environment. Many different factors including the interaction in the sizing agent, the interaction between the sizing agent and textile fibers, and desizing agent influence the desizing efficiency of sizing agents. During the last decades, sizing with new agents with enhanced properties have been extensively studied. However, reviews on desizability, biodegradability of sizing agents and their mechanism seem very rare. In this review, methods of desizing which are frequently used and the factors that influence desizing mechanism and biodegradability have been discussed. Knowledge about the effect of these factors in desizing and biodegradation, and the mechanisms could serve as a platform to develop sizing agents with good desizing efficiency and biodegradability. [ABSTRACT FROM AUTHOR]

Vermicomposting is a promising method for corn stover management to achieve bioresource recovery and environmental protection. Most β-glucosidases, which limit the cellulose degradation rate during vermicomposting of corn stover, belong to glycoside hydrolase family 1 (GH1). This study was conducted with different earthworm densities to quantify the GH1 gene abundance and investigate the evolution of GH1 cellulase-producing microbial communities using qPCR and pyrosequencing. The results showed that β-glucosidase activity, GH1 gene abundance, TOC, and microbial communities carrying the GH1 gene were affected by processing time and earthworm density. After introducing earthworms, β-glucosidase activity increased to 1.90–2.13 U/g from 0.54 U/g. The GH1 gene abundance of treatments with earthworms (5.82E+09–6.70E+09 copies/g) was significantly higher than that of treatments without earthworms (2.48E+09 copies/g) on Day 45. Earthworms increased the richness of microbial communities. The relative abundances of Sphingobium and Dyadobacter, which are dominant genera harboring the GH1 gene, were increased by earthworms to peak values of 23.90% and 11.20%, respectively. Correlation analysis showed that Sphingobium, Dyadobacter, Trichoderma, and Starkeya were positively associated with β-glucosidases. This work sheds new light on the mechanism of cellulose degradation during vermicomposting at the molecular level. [ABSTRACT FROM AUTHOR]

In the recent past, an increasing interest is mostly observed in using microwave and ultrasonic irradiation to aid the biological conversion of waste materials into value-added products. This study is focused on various individual impacts of microwaves and ultrasonic waves for the treatment of biomass before the synthesis of value-added products. Following, a comprehensive review of the mechanisms governing microwaves and ultrasonication as the treatment methods, their effects on biomass disruption, solubilization of organic matter, modification of the crystalline structure, enzymatic hydrolysis and production of reducing sugars was performed. However, based on the lab-scale experiments evaluated, microwaves and ultrasonication were studied to be economically and energetically ineffective despite their beneficial effects on the waste biomass. This article reviews some of the difficulties associated with using microwaves and ultrasonic irradiation for the efficient processing of waste biomasses and identified some potential directions for future study. [ABSTRACT FROM AUTHOR]

Ligninases and hemicellulases are crucial as accessory enzymes to increase the enzymatic hydrolysis of lignocellulose, boosting sugars production from which biofuels and bioproducts could be obtained. In order to find new sources of these accessory enzymes, this study evaluates the potential of laccase and mannanase enzymes from Streptomyces ipomoeae for improving the conventional hydrolysis with commercial cellulases of steam-pretreated softwood. For that, different laccase treatment and mannanase supplementation strategies were performed. S. ipomoeae laccase increased both glucose and xylose production (17.8% and 9.3%, respectively), which was attributed to a removal of phenols of 29%. Moreover, the combination of laccase and alkaline extraction produced a lignin reduction of 16.2%, improving the glucose and xylose production by almost 41.3% and 44.9%, respectively. On the other hand, the supplementation of S. ipomoeae mannanase to the hydrolysis 24 h before the addition of cellulases increased the glucose (18.4%), xylose (12.3%), and mannose (47.2%) production. [ABSTRACT FROM AUTHOR]

Emergence of "severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)" causing "COVID-19" or "coronavirus disease 19" as pandemic has got worldwide attention towards hygiene as the first line of defense for the infection control. It is first line of defense not only from COVID-19 but also from other infectious diseases caused by deadly pathogens such as cholera, hepatitis, tuberculosis, polio, etc. Absence of any particular vaccine or treatment let World Health Organization (WHO) recommend to the public to maintain social distancing along with regularly washing their hands with soap, sanitize their hands (where washing is not possible), and disinfect their belongings and buildings to avoid the infection. Out of various formulations available in the market, WHO has recommended alcohol-based hand sanitizers, which mainly comprise of ethanol, isopropyl alcohols, and hydrogen peroxides in different combinations due to their high potential to kill the broad range of pathogens including bacterial, viral, fungal, helminthes, etc. Therefore, alcohol-based sanitizers are in high demand since centuries to prevent infection from pathogenic diseases. Ethanol is the most common and popular alcohol in terms of vanishing wide range of pathogens, convenient to use and its production. Ethanol is produced worldwide and is used in various sectors, e.g., beauty and cosmetics, food and beverages, and as the most demanding gasoline additive. The present review is focused on the ethanol production in India, its diversified applications emphasizing hand sanitizers with discussions on formulation of sanitizer and disinfectants, and viability of lignocellulosic and food grain–based ethanol. The review article also emphasizes on the technological details of 1G and 2G ethanol production, their associated challenges, and inputs for the improved ethanol yields so as to strengthen the supply chain of ethanol in India, and making "Atmanirbhar Bharat" (Self-reliant India) campaign of Indian government successfully viable. [ABSTRACT FROM AUTHOR]

Microbial exopolysaccharides, especially from thermophiles, are gaining attention due to their thermostability and reduced viscosity at elevated temperatures which make them suitable candidates for pharmaceutical, cosmetics and food industries. This study aims to identify potential of a novel thermophile for the production of high amounts of exopolysaccharide. It also reports suitable process parameters for growth of novel thermophile in exopolysaccharide production medium and determination of optimum glucose concentration as its production generally requires high amount of glucose making the process cost intensive. Thermophilic bacteria, from a local hot spring, were screened for the production of exopolysaccharide, and growth kinetics of the best producer, Brevibacillus borstelensis MK878423, was studied. The growth study of bacterium revealed optimum time of production as 40 h, and maximum product was formed at 30 g/l glucose. The logistic growth curve of the bacterium was analysed, and kinetic rate constants for substrate utilization were estimated by modified Luedeking-Piret kinetic model. The specific growth rate of the bacterium was calculated to be 0.0166 h−1 with kinetic rate constants as − 18.953 (α) and 90.655 (β) for Luedeking-Piret substrate. This is the first report on the production of exopolysaccharide by a strain of Brevibacillus borstelensis. Understanding the kinetic rate constants for substrate consumption will help in extrapolating the system of microbial exopolysaccharide production from agricultural wastes with high glucose content. The determination of optimal glucose concentration will also help in utilizing biowastes as substrates for exopolysaccharide production following biorefinery concept as wastes are utilized for the production of value-added chemicals. [ABSTRACT FROM AUTHOR]

Diversity lifts the productivity of any ecosystem as all the species have a vital role to play that is present within the ecosystem. The characterization is essential to delve into the ecological functions of microbial communities and discover the type of microorganisms present within the ecosystem. As microbial diversity in ecosystems responds to environmental disturbances, it functions as a marker to indicate the change in such ecosystems. Mine ecology differs significantly from other habitats due to the presence of acidic runoff. This paper provides insight into the diversity of cultivable bacteria isolated from lignite mines located in south Gujarat. A total of 67 heterotrophic isolates were successfully cultivated from the collected solid and water samples of the Rajpardi and Tadkeshwar Lignite mine sites. The isolates were characterized morphologically and biochemically, and intra- and extracellular enzyme synthesis were studied. Moreover, the relative density and frequency of cultivated isolates from the samples were calculated. The similarity and evenness of the heterotrophic isolated were studied by calculating diversity indices such as Shannon and Simpson. Alpha diversity was calculated in PAST software to analyse the similarity between the selected two mine sites. This research also explored the relationship between the variance in heterotrophic microbial diversity and substrate utilization richness of the studied lignite mines of Gujarat. [ABSTRACT FROM AUTHOR]

With the ever-increasing environmental concerns and the rush to meet the United Nations' sustainable development goals, it is an uphill task to find a single source of energy that may completely replace fossil fuels. Energy derived from biomass is an attractive alternative to transportation fuel along with electricity and heat generation. The bioenergy from agricultural biomass, food crops, forest residue, algae, and municipal waste can also allow sustainable waste management. However, most bioenergy conversion facilities are still in the research or pilot stage and have many technological and economical limitations. This critical review provides an insight into different recourses of biomass, bioenergy conversion routes, and other challenges to biofuel production. An attempt has been made to elucidate the novel technological advancements made in these processes like bio-chemical looping combustion, torrefaction, and photo- and dark fermentation. The integration of these systems with artificial intelligence and machine learning-based modeling and optimization is also discussed to bring insight to alternate advancement routes. A comparison of the conversion methods is attempted to bring insight into the feasibility, sustainability, and advancement of bioenergy production and its commercialization. [ABSTRACT FROM AUTHOR]

The Bacillaceae family members are considered to be a good source of microbial factories for biotechnological processes. In contrast to Bacillus and Geobacillus, Anoxybacillus, which would be thermophilic and spore-forming group of bacteria, is a relatively new genus firstly proposed in the year of 2000. The development of thermostable microbial enzymes, waste management and bioremediation processes would be a crucial parameter in the industrial sectors. There has been increasing interest in Anoxybacillus strains for biotechnological applications. Therefore, various Anoxybacillus strains isolated from different habitats have been explored and identified for biotechnological and industrial purposes such as enzyme production, bioremediation and biodegradation of toxic compounds. Certain strains have ability to produce exopolysaccharides possessing biological activities including antimicrobial, antioxidant and anticancer. This current review provides past and recent discoveries regarding Anoxybacillus strains and their potential biotechnological applications in enzyme industry, environmental processes and medicine. [ABSTRACT FROM AUTHOR]

The growing global population and higher living standards instantly demand the transition in the direction of a sustainable food system. A substantial section of means and agricultural lands are presently committed to protein-rich feed production to rear livestock for human consumption. Conversely, accelerated farming activities and the food industry have rendered a drastic increase in waste which impair the economic and environmental sustainability of the ecosystem. This situation emerges the need for developing an integrated technology for waste management and to improve sustainability footprints. Microbial protein (MP) production based on renewable electron and carbon sources has the potential as a substitute protein source. MP production for animal feed use is growing fast and is derived from bacteria, algae, and fungi including yeast. MP produced from all types of microbes is currently commercialized and in use. However, novel methods and processes are also under investigation to make MP production more economical and sustainable. Current research on MP has concentrated on the valorization of waste materials by using high protein content-containing microorganisms, which can then be used in animal feed. Using such kind of integrated approach, the agroindustry waste resources upcycling can contribute towards finding sustainable, cheaper, and environment-friendly protein sources. This review first describes the potential waste feedstock for MP production and summarizes the recent progress in the application of MP-producing microorganisms including fungus, yeast, bacteria, and phototrophic microbes. Bioprocesses, and production technology advances for MP production have been explored and discussed in detail. Finally, the MP application as animal feed, its challenges, and future perspectives in research have been evaluated. [ABSTRACT FROM AUTHOR]

The present study was carried out with the objective of isolation, screening and optimization of hexose fermenting butanologens. A bacterium, NIBE-A1, was isolated and screened for the production of butanol and identified as Clostridium pasteurianum NIBE-A1. The effects of pH and temperature were investigated and optimized through response surface methodology to obtain maximum specific growth rate, µmax (h−1) and total solvent production (g l−1). The optimized constraints such as pH and temperature for growth were found to be 6.5 and 40 °C, respectively. The constraints such as pH and temperature for total solvent production were found to be 5.01 and 34.2 °C. Under optimized conditions, the total solvent titre of 13.23 ± 0.14 g l−1 was obtained with 0.19 ± 0.08 g g−1 of butanol yield and 0.28 ± 0.11 g l−1 h−1 of butanol productivity. This study revealed the promising potential of the isolated bacterium for butanol production. [ABSTRACT FROM AUTHOR]

Extremophilic microorganisms, which are resistant to extreme levels of temperature, salinity, pH, etc., have become popular tools for biotechnological applications. Due to their availability and cost-efficacy, enzymes from extremophiles are getting the attention of researchers and industries in the field of biocatalysis to catalyze diverse chemical reactions in a selective and sustainable manner. In this mini-review, we discuss the advantages of Halomonas elongata as moderate halophilic bacteria to provide suitable enzymes for biotechnology. While enzymes from H. elongata are more resistant to the presence of salt compared to their mesophilic counterparts, they are also easier to produce in heterologous hosts compared with more extremophilic microorganisms. Herein, a set of different enzymes (hydrolases, transferases, and oxidoreductases) from H. elongata are showcased, highlighting their interesting properties as more efficient and sustainable biocatalysts. With this, we aim to improve the visibility of halotolerant enzymes and their uncommon properties to integrate biocatalysis in industrial set-ups. Keypoints: • Production and use of halotolerant enzymes can be easier than strong halophilic ones. • Enzymes from halotolerant organisms are robust catalysts under harsh conditions. • Halomonas elongata has shown a broad enzyme toolbox with biotechnology applications. [ABSTRACT FROM AUTHOR]

Parageobacillus thermoglucosidasius is a thermophilic Gram-positive bacterium, which is a promising host organism for sustainable bio-based production processes. However, to take full advantage of the potential of P. thermoglucosidasius, more efficient tools for genetic engineering are required. The present study describes an improved shuttle vector, which speeds up recombination-based genomic modification by incorporating a thermostable sfGFP variant into the vector backbone. This additional selection marker allows for easier identification of recombinants, thereby removing the need for several culturing steps. The novel GFP-based shuttle is therefore capable of facilitating faster metabolic engineering of P. thermoglucosidasius through genomic deletion, integration, or exchange. To demonstrate the efficiency of the new system, the GFP-based vector was utilised for deletion of the spo0A gene in P. thermoglucosidasius DSM2542. This gene is known to be a key regulator of sporulation in Bacillus subtilis, and it was therefore hypothesised that the deletion of spo0A in P. thermoglucosiadius would produce an analogous sporulation-inhibited phenotype. Subsequent analyses of cell morphology and culture heat resistance suggests that the P. thermoglucosidasius ∆spo0A strain is sporulation-deficient. This strain may be an excellent starting point for future cell factory engineering of P. thermoglucosidasius, as the formation of endospores is normally not a desired trait in large-scale production. [ABSTRACT FROM AUTHOR]

The biosphere is subjected to low temperatures in both aquatic and terrestrial environments. Psychrophilic and psychrotolerant bacteria that colonize cold environments, such as Antarctica and Arctic continents, are able to survive in inhospitable conditions. This is attributed to some cold adaptations developed by these microorganisms over the years, such as the synthesis of carotenoid pigments, modification of membrane structure and production of biosurfactants (BS) and/or bioemulsifiers (BE). BS and BE are bioproducts produced by microorganisms that are less toxic than chemically synthesized surfactants. The physical and chemical properties of these substances make them applicable in different areas, such as bioremediation of contaminated areas, microbial enhanced oil recovery, pharmaceutical, cosmetics and food industries. Additionally, studies about BS and BE produced by psychrophiles and psychrotolerants are still very recent in relation to the studies carried out with mesophilic microorganisms and their products. This review aims to compile information on the mechanisms of adaptation of microorganisms in cold environments with a focus on the production of BS and BE and their potential biotechnological applications. [ABSTRACT FROM AUTHOR]

Chromium (Cr) compounds are usually toxins and exist abundantly in two different forms, Cr(VI) and Cr(III), in nature. Their contamination in any environment is a major problem. Many extreme environments including cold climate, warm climate, acidic environment, basic/alkaline environment, hypersaline environment, radiation, drought, high pressure, and anaerobic conditions have accumulated elevated Cr contamination. These harsh physicochemical conditions associated with Cr(VI) contamination damage biological systems in various ways. However, several unique microorganisms belonging to phylogenetically distant taxa (bacteria, fungi, and microalgae) owing to different and very distinct physiological characteristics can withstand extremities of Cr(VI) in different physicochemical environments. These challenging situations offer great potential and extended proficiencies in extremophiles for environmental and biotechnological applications. On these issues, the present review draws attention to Cr(VI) contamination from diverse extreme environmental regions. The study gives a detailed account on the ecology and biogeography of Cr(VI)-resistant microorganisms in inhospitable environments, and their use for detoxifying Cr(VI) and other applications. The study also focuses on physiological, multi-omics, and genetic engineering approaches of Cr(VI)-resistant extremophiles. [ABSTRACT FROM AUTHOR]

This study investigated the effect of enzymatic and hydrothermal pretreatment approaches on the solubilization of organic matter, structure, and biogas yield from microalgal biomass. The soluble chemical oxygen demand (sCOD) concentration increased by 1.21–3.30- and 5.54–6.60-fold compared to control by enzymatic and hydrothermal pretreatments respectively. The hydrothermal pretreatment affected the structural changes in the microalgal biomass markedly; nonetheless, increased enzymatic concentration also had a definite effect on it as determined by qualitative approaches like scanning electron microscopy and Fourier transform infrared spectroscopy. Also, the hydrothermal pretreatment (100 °C for 30 min) resulted in the highest biogas production potential (P) of 765.37 mLg−1 VS at a maximum biogas production rate (Rm) of 22.66 mLg−1 day−1 with a very short lag phase (λ) of 0.07 days. The biogas production of pretreated microalgal biomass particularly at higher enzyme dose (20%, 24 h) and higher hydrothermal pretreatment temperature (120 °C, 30 min) showed a significant but weak correlation (R = 0.53) with sCOD, thus demonstrating that the less organic matter was used up for the biogas production. The modified Gompertz model explained the anaerobic digestion of microalgal biomass more accurately and had a better fit to the experimental data comparatively because of the low root mean square error (3.259–16.728), residual sum of squares (78.887–177.025), and Akaike's Information Criterion (38.605–62.853). [ABSTRACT FROM AUTHOR]

The present work performs the polyphasic characterization of a novel cyanobacterial species Scytonema ambikapurensis isolated from an Indian hot spring and evaluates its wastewater bioremediation potential. While the physicochemical analyses of the wastewater indicated high load of nutrients and metals, the wastewater bioremediation experiment performed using the test cyanobacterium denoted the removal of 70 and 86% phosphate, 49 and 66% sulfate, 96 and 98% nitrate, 91 and 92% nitrite, 95 and 96% ammonia, 66 and 72% chloride, 79 and 81% zinc, 68 and 80% nickel, 81 and 90% calcium, and 80 and 90% potassium from the autoclaved and un-autoclaved wastewater, respectively, after 20 days of culturing. The kinetics study of zinc and nickel removal from wastewater revealed that the cyanobacterium employed sequential biosorption (by following pseudo-second-order kinetics model) and bioaccumulation methods to remove these two metals. The quality of the autoclaved and un-autoclaved wastewater was further improved by the cyanobacterium through reduction of hardness by 74 and 81%, respectively. In wastewater, the cyanobacterium not only enhanced its biomass, chlorophyll and carbohydrate contents, but also produced small amount of released and high capsular exopolysaccharide (EPS). The FTIR and TGA analyses of capsular EPS unraveled that it was a negatively charged sulfated biomolecule having thermostability up to 240 °C, which suggested its possible use as excellent emulsifying, viscosifying, and biosorption agent. The credibility of this EPS as biosorption agent was ascertained by evaluating its metal chelating ability. Finally, the experimental data denoting the ability of S. ambikapurensis to bioremediate wastewater and simultaneously produce EPS was statistically validated by PCA1-pollutant removal model and the PCA2-cellular constituent model, respectively. Briefly, the study discloses that the cyanobacterium has huge biotechnological and industrial importance as it bioremediates wastewater and simultaneously produces thermostable exopolysaccharide. [ABSTRACT FROM AUTHOR]

Deficiency of trace metals exacerbates instability in the methanogenic phase of two-phase thermophilic AD. The addition of a micronutrient supplement containing calcium, magnesium, cobalt and nickel was found to help process recovery, increasing methane production by up to 40%. In this study, next gen sequencing was used to identify the changes brought by addition of the micronutrients in the bacterial community of the methanogenic phase of food waste processing. The diversity of the community before supplementation was considerably low and a single species of Phylum Thermotogae was the sole dominant bacterial group. The addition of a micronutrient supplement comprising of Ca, Mg, Co and Ni caused a potent increase in the diversity of the community and species belonging to Arcobacter, Clostridium, Pseudomonas, Bacteroides and Coprothermobacter were particularly enriched. This suggested that the action of the micronutrients resulted in an increase in the functional diversity and redundancy of the bacterial community and limiting hydrogenotrophic methanogenesis in favour of acetotrophic methanogenesis. These factors would contribute to the observed increased stability and higher productivity in the micronutrient supplemented thermophilic AD process. [ABSTRACT FROM AUTHOR]

The main objective of our work is to optimize the 1st step of the dilute sulfuric acid hydrolysis of Moroccan sugar beet pulp. The optimal conditions were not only determined using the response surfaces methodology (RSM). They were defined by applying a multi-objective optimization using a desirability function. The effects of temperature (80–130 °C), sulfuric acid concentration (0.75–1.5 % v/v), and time (40–120 min) on the production of pentoses, hexoses, furfural, and 5-hydroxymethylfurfural (HMF) were determined by experiment according to a central composite design (CCD). These experimental data were exploited to develop four statistical models by RSM, relating the production of each product of pretreated pulp to the operating conditions. All these models produced very satisfactory results, in term of correlation coefficients and student test. These models have been used for a multi-objective optimization to maximize pentoses and hexoses production, and minimize concentrations of furfural and HMF, simultaneously. The optimal conditions were 130 °C for temperature, 0.75 (%, v/v) for sulfuric acid concentration, and 120 min for time. These conditions allowed 85.68 % of pentoses, 18.6% of hexoses, 8.53 % of furfural, and 6.58 % of HMF. [ABSTRACT FROM AUTHOR]

This study examined Cr(VI) removal efficiency of maize stalk biochar (MSB) from waste water. Equilibrium isotherm results were examined by Langmuir, Freundlich, and Temkin isotherms. The adsorption was found to fit well with the Freundlich and Temkin isotherm models, with R2 values of 0.994 and 0.909, respectively. Temkin indicates the process to be exothermic. The values of the thermodynamic parameter (∆G0) suggested that the adsorption was reasonable and natural. The FT-IR bands were recorded to explore the functional groups available to bind Cr(VI) ions). The SEM–EDS and TEM results show the morphology of the studied adsorbent and C/O ratio present in MSB. XRD and XPS analyses of the adsorbents before and after the reaction indicate that co-precipitation occurred during adsorption. Brunauer, Emmett, and Teller (BET) were recorded for MSB to understand the nature of the surface and pore space present. Thus, MSB has the potential to remove hexavalent chromium ions from wastewater, and removal efficiency is 81%. Microbes present in the soil effectively assisted the desorption of chromium ions from MSB's active sites with concurrent power generation of 359 mV in microbial fuel cells. [ABSTRACT FROM AUTHOR]

Bioreduction of Cr(VI) is cost-effective and environmentally friendly, however, the slow bioreduction rate limits its application. In this study, the potential synergistic enhancement of Cr(VI) bioreduction by shewanella oneidensis MR-1 (S. oneidensis) with goethite and riboflavin (RF) was investigated. The results showed that the S. oneidensis reaction system reduce 29.2% of 20 mg/L Cr(VI) after 42 h reaction, while the S. oneidensis/goethite/RF reaction system increased the Cr(VI) reduction rate to 87.74%. RF as an efficient electron shuttle and Fe(II) from goethite bioreduction were identified as the crucial components in Cr(VI) reduction. XPS analysis showed that the final precipitates of Cr(VI) reduction were Cr(CH3C(O)CHC(O)CH3)3 and Cr2O3 and adhered to the bacterial cell surface. In this process, the microbial surface functional groups such as hydroxyl and carboxyl groups participated in the adsorption and reduction of Cr(VI). Meanwhile, an increase in cytochrome c led to an increase in electron transfer system activity (ETSA), causing a significant enhancement in extracellular electron transfer efficiency. This study provides insight into the mechanism of Cr(VI) reduction in a complex environment where microorganisms, iron minerals and RF coexist, and the synergistic treatment method of Fe(III) minerals and RF has great potential application for Cr(VI) detoxification in aqueous environment. [ABSTRACT FROM AUTHOR]

Pretreatment of biomass is one of the most challenging steps in the process of second-generation (2G) ethanol and biochemical production. Dilute acid pretreatment is a widely adapted and convenient method to recover pentose (C5) as well as hexose (C6) sugars due to its featured solubilization of hemicellulose and cellulose before and after enzymatic saccharification, respectively. In the present study, dilute sulfuric acid (H2SO4) pretreatment of sugarcane bagasse (SCB) was statistically optimized using the face-centered composite design (FCCD) of response surface methodology (RSM) in terms of acid concentration (0.1–3% v/v), solid loading (5–20% w/v) and residence time (15–60 min) at constant temperature of 121 °C followed by enzymatic hydrolysis using commercial cellulase (Novozymes Cellic CTec2) for enhanced combined sugar yield (CSY) comprising of C5 and C6 sugars in pretreated as well as saccharified hydrolysates. Optimized process parameters found in the study were 2.18% (v/v) acid; 14.35% (w/v) solid loading; and 29.49 min residence time. CSY under optimized conditions was found to be 521.42 ± 7.2 g/kg raw SCB with 72.06 ± 1.0% sugars recovered out of the maximum theoretical sugars present in the raw biomass. Total reducing sugar yields in pretreated and saccharified hydrolysates were found to be 215.28 ± 2.4 and 306.14 ± 5.3 g/kg raw SCB, respectively. Morphological and structural changes in optimized pretreated and saccharified biomass further validated the efficiency of optimized pretreatment applied in the present study. The maximum ethanol concentration, volumetric productivity and yield from released sugars were calculated as 10.82 ± 2.2 g/L, 0.45 ± 0.9 g/L/h and 0.42 g/g-glucose consumed or 71.45 ± 2.5 g/kg raw SCB, respectively. Ethanol yield obtained from the fermentation of dilute H2SO4-pretreated SCB was corresponding to 82.4% of the theoretical ethanol yield. [ABSTRACT FROM AUTHOR]

Biomethanation is a temperature-dependent process, and in the cold regions where temperature mostly remains below 20 °C, it acts as a crucial limiting factor. The biomethanation process with efficient cold-tolerant anaerobes and other advanced techniques, including reliable digester designs, cost-effective insulation strategies, and additives, can help increase methane production efficiency under low ambient temperature. In cold regions, traditional fuel sources like forest wood, charcoal, agricultural residues, or cow dung cakes are used for cooking and heating, leading to increased greenhouse gas emissions. Thus, biogas is a promising fuel to replace traditional fuels and helps reduce the greenhouse effect to a great extent. The current review article has highlighted the role of cold-tolerant methanogens, different digester designs with a special focus on insulation techniques, co-digestion, and additives. The review also discusses different upgradation techniques to generate pure methane as a substitute for natural gas. Additionally, life cycle assessment analysis is also carried out focusing on the reduction of greenhouse gas emissions to show higher biogas production over traditional biogas systems. Overall, the importance of improved biomethanation in cold regions has been discussed in this review article. [ABSTRACT FROM AUTHOR]

Stimulating indigenous microbes to reduce aqueous U(VI) to insoluble U(IV) by adding an electron donor has been applied as an applicable strategy to remediate uranium-contaminated groundwater in situ. However, biogenic U(IV) minerals are susceptible to oxidative remobilization after exposure to oxygen. To enhance the stability of the end product, glycerol phosphate (GP) was selected to treat artificial uranium-containing groundwater at different pH values (i.e., 7.0 and 5.0) with glycerol (GY) as the control group. The results revealed that removal ratios of uranium with GP were all higher than those with GY, and reduced crystalline U(IV)-phosphate and U(VI)-phosphate minerals (recalcitrant to oxidative remobilization) were generated in the GP groups. Although bioreduction efficiency was influenced at pH 5.0, the stability of the end product with GP was elevated significantly compared with that with GY. Mechanism analysis demonstrated that GP could activate bioreduction and biomineralization of the microbial community, and two stages were included in the GP groups. In the early stage, bioreduction and biomineralization were both involved in the immobilization process. Subsequently, part of the U(VI) precipitate was gradually reduced to U(IV) precipitate by microorganisms. This work implied that the formation of U-phosphate minerals via bioreduction coupled with biomineralization potentially offers a more effective strategy for remediating uranium-contaminated groundwater with long-term stability. [ABSTRACT FROM AUTHOR]