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The Arctic region harbors elite extremophiles skilled in producing novel exopolysaccharides (EPS) to cope with extreme environmental conditions. In the present study, psychrotrophic microorganisms isolated from Svalbard glacier soil were investigated for EPS production. Pseudomonas frederiksbergensis BBL-P-9 proved higher EPS production under different substrate-feeding strategies. On feeding with pure glucose (30 g L−1) and xylose (10 g L−1), this bacterium produced 12.67 g L−1 and 6.38 g L−1 of EPS, respectively. Interestingly, on examining different lignocellulosic biomass hydrolysates as the substrates, P. frederiksbergensis BBL-P-9 produced 9.42 g L−1 of EPS using pinewood hydrolysate (glucose content adapted to 30 g L−1). Furthermore, this bacterium evidenced tolerance to the plant biomass pre-treatment-derived side products in the following order: acetate>furfural>vanillin>5-hydroxymethylfurfural. The composition of EPS was altered with the type and concentration of the carbon substrate fed. However, β-D-glucopyranose (20~34%), β-D-mannopyranose (15~22%), and β-D-galactopyranose (17~27%) were the dominant monosaccharides detected in P. frederiksbergensis BBL-P-9 EPS. [ABSTRACT FROM AUTHOR]

Plant biomass, one of the most abundant and renewable resources obtained from plants has gained much interest among researchers. Recently, more attention has shifted towards aquatic plant biomass as a potential alternative feedstock for producing bioenergy and other high-value products. Regardless of the low lignin content, invasive aquatic plant (IAP) biomass should undergo pretreatments to disrupt the recalcitrant supramolecular structure to minimize the conversion time, operational cost, and ensure optimal yield. Three major types of Lignocellulosic biomass (LB) pretreatments including physical, chemical, and biological are predominantly applied independently or in combination depending on the type of biomass. This review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method for the compilation of existing literature on aquatic plant biomass pretreatment. A total of 185 peer-reviewed articles on the pretreatment of aquatic LB published between the year 2018 to 2022 were retrieved from the Elsevier, MDPI, and Springer databases. This study revealed the water hyacinth (WH) as the most researched IAP and thus identifies the need for more studies on a variety of IAPs that have proven to produce high-value products and biofuels that are comparable to petroleum products. [ABSTRACT FROM AUTHOR]

The present investigation deals with production of biochar using various agricultural and non-agricultural waste biomass followed by sorption of methylene blue (MB) dye. The optimization of pyrolysis temperature, dye solution pH, incubation temperature, and time was performed using response surface methodologies (RSM). Analytical tools like Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and total organic carbon (TOC) were employed to analyze changes in the material after pyrolysis. The water hyacinth biochar showed 100% predicted and 98% actual sorption capability for MB dye (3000 mg/L) after statistically optimized conditions like pyrolysis temperature (1000 °C), pH (8), incubation temperature (60 °C), and incubation time (1 h). The cytotoxicity, phytotoxicity, and hemolysis studies indicated that the toxicity of the MB dye was significantly decreased after treating MB dye solution with water hyacinth biochar. Therefore, the present results reveal an easy and economical dye removal strategy using various waste biomass-derived biochars. [ABSTRACT FROM AUTHOR]

Polyhydroxybutyrate (PHB) is a bio-based, biodegradable and biocompatible plastic that has the potential to replace petroleum-based plastics. Lignocellulosic biomass is a promising feedstock for industrial fermentation to produce bioproducts such as polyhydroxybutyrate (PHB). However, the pretreatment processes of lignocellulosic biomass lead to the generation of toxic byproducts, such as furfural, 5-HMF, vanillin, and acetate, which affect microbial growth and productivity. In this study, to reduce furfural toxicity during PHB production from lignocellulosic hydrolysates, we genetically engineered Cupriavidus necator NCIMB 11599, by inserting the nicotine amide salvage pathway genes pncB and nadE to increase the NAD(P)H pool. We found that the expression of pncB was the most effective in improving tolerance to inhibitors, cell growth, PHB production and sugar consumption rate. In addition, the engineered strain harboring pncB showed higher PHB production using lignocellulosic hydrolysates than the wild-type strain. Therefore, the application of NAD salvage pathway genes improves the tolerance of Cupriavidus necator to lignocellulosic-derived inhibitors and should be used to optimize PHB production. [ABSTRACT FROM AUTHOR]

Biohydrogen is a clean and efficient source of energy produced easily by anaerobic systems. Therefore, the discovery of novel and efficient production methods and utilization of inexpensive starting material are crucial for economical biohydrogen production. In this study, novel hydrogen producing bacterial strain Clostridium sp. SH25 was screened from the anaerobic sludge obtained from a water treatment plant, which showed a higher hydrogen-producing activity on glycerol than other strains. The effective hydrogen production was evaluated under varying anaerobic culture conditions, and the optimum temperature, initial pH, additional NaCl concentration, and inoculum size were 37 °C, 6.0, 0%, and 10% (v/v), respectively. The cumulative hydrogen production volume from crude glycerol was 24.30±1.07 ml after 36 h. To test the practical application of biohydrogen, a 20 ml culture of Clostridium sp. SH25 was incubated for 12 h and directly applied to a small hydrogen car unit operated for 19.05±0.33 s with 8.37 ± 0.21 m displacement. Overall, identification of the efficient Clostridium sp. SH25 strain resulted in the production of a large amount of biohydrogen, which further supported the operation of a small hydrogen car. This implied a possible application of biosystems in biohydrogen production. [ABSTRACT FROM AUTHOR]

L-pipecolic acid (L-PA) is a key chiral intermediate in the synthesis of many important drugs. However, there is a lack of research on the efficient extraction and purification process for L-PA. Here, eleven different organic solvents were evaluated for selective extraction of L-PA by physical extraction. Among these solvents, methyl ethyl ketone (MEK) showed the highest extraction yield of L-PA, and analysis of the linear solvation energy relationship between the solvents showed that MEK was the most suitable solvent for L-PA extraction. The highest extraction yield of L-PA was 37% under optimal conditions (pH 6, 20°C, 30 min and ratio of 1). Furthermore, the repetitive extraction of L-PA from bioconversion solution was also investigated. The MEK gave high purity of L-PA (93.1% and 22.8% yield) from the bioconversion mixture. Our study is the first approach to show easy recovery of L-PA by liquid-liquid extraction and the application of MEK extraction method to L-lysine bioconversion mixture. [ABSTRACT FROM AUTHOR]

The present study was aimed to investigate brilliant green (BG) dye sorption onto soybean straw biochar (SSB) prepared at 800 °C and further understanding the sorption mechanism. Sorption kinetic models such as pseudo-first and pseudo-second order were executed for demonstrating sorption mechanism between the dye and biochar. Results of kinetics study were fitted well to pseudo-second-order kinetic model (R2 0.997) indicating that the reaction followed chemisorption mechanism. Furthermore, the effect of various parameters like sorbent dose, dye concentration, incubation time, pH and temperature on dye sorption was also studied. The maximum dye removal percentage and sorption capacity for SSB (800 °C) within 60 min were found to be 99.73% and 73.50 mg g− 1, respectively, at pH 8 and 60 °C temperature, whereas adsorption isotherm studies showed a higher correlation coefficient values for Freundlich model (R2 0.990–0.996) followed by Langmuir model suggesting that sorption process was multilayer. The characterization of biomass and biochar was performed with the aid of analytical techniques like scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) theory, X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). FTIR analysis showed active groups on biochar surface. BET study revealed higher surface area of biochar (194.7 m2/g) than the biomass (12.84 m2/g). Besides, phyto- and cytogenotoxic studies revealed significant decrease in the toxicity of dye containing water after treating with SSB. Therefore, this study has proved the sorption potential of soybean straw biochar for BG dye and could be further considered as sustainable cost-effective strategy for treating the textile dye-contaminated wastewater. [ABSTRACT FROM AUTHOR]

Cadaverine, 1,5-diaminopentane, is one of the most promising chemicals for biobased-polyamide production and it has been successfully produced up to molar concentration. Pyridoxal 5′-phosphate (PLP) is a critical cofactor for inducible lysine decarboxylase (CadA) and is required up to micromolar concentration level. Previously the regeneration of PLP in cadaverine bioconversion has been studied and salvage pathway pyridoxal kinase (PdxY) was successfully introduced; however, this system also required a continuous supply of adenosine 5′-triphosphate (ATP) for PLP regeneration from pyridoxal (PL) which add in cost. Herein, to improve the process further a method of ATP regeneration was established by applying baker's yeast with jhAY strain harboring CadA and PdxY, and demonstrated that providing a moderate amount of adenosine 5′-triphosphate (ATP) with the simple addition of baker's yeast could increase cadaverine production dramatically. After optimization of reaction conditions, such as PL, adenosine 5′-diphosphate, MgCl2, and phosphate buffer, we able to achieve high production (1740 mM, 87% yield) from 2 M l-lysine. Moreover, this approach could give averaged 80.4% of cadaverine yield after three times reactions with baker's yeast and jhAY strain. It is expected that baker's yeast could be applied to other reactions requiring an ATP regeneration system. [ABSTRACT FROM AUTHOR]

γ-Aminobutyric acid (GABA), an important fine chemical in pharmacotherapy and food industries, is used as a novel material in the nylon industry and has attracted attention for its potential application in large scale production. Search for new genes and strains, development of efficient reaction systems, such as fermentation and bioconversion, and use of cheap starting material like monosodium glutamate (MSG) can make GABA production using less expensive bulk chemicals possible. Therefore, in this study, we constructed a recombinant Escherichia coli whole-cell system for GABA production that expressed glutamate decarboxylase (GAD) from Lactobacillus brevis and used MSG as the starting material. We also optimized the reaction conditions for MSG to GABA conversion, such as citrate buffer concentration, pyridoxal 5′te concentration, temperature, MSG concentration, and cell density (OD600). The optimized whole-cell system converted MSG to GABA via seven repetitive cycles resulting in an average conversion rate of 86% (71.7 mM/h) within 42 h. [ABSTRACT FROM AUTHOR]

Bacteria have evolved a defense system to resist external stressors, such as heat, pH, and salt, so as to facilitate survival in changing or harsh environments. However, the specific mechanisms by which bacteria respond to such environmental changes are not completely elucidated. Here, we used halotolerant bacteria as a model to understand the mechanism conferring high tolerance to NaCl. We screened for genes related to halotolerance in Halomonas socia, which can provide guidance for practical application. Phospholipid fatty acid analysis showed that H. socia cultured under high osmotic pressure produced a high portion of cyclopropane fatty acid derivatives, encoded by the cyclopropane-fatty acid-acyl phospholipid synthase gene (cfa). Therefore, H. socia cfa was cloned and introduced into Escherichia coli for expression. The cfa-overexpressing E. coli strain showed better growth, compared with the control strain under normal cultivation condition as well as under osmotic pressure (> 3% salinity). Moreover, the cfa-overexpressing E. coli strain showed 1.58-, 1.78-, 3.3-, and 2.19-fold higher growth than the control strain in the presence of the inhibitors furfural, 4-hydroxybenzaldehyde, vanillin, and acetate from lignocellulosic biomass pretreatment, respectively. From a practical application perspective, cfa was co-expressed in E. coli with the polyhydroxyalkanoate (PHA) synthetic operon of Ralstonia eutropha using synthetic and biosugar media, resulting in a 1.5-fold higher in PHA production than that of the control strain. Overall, this study demonstrates the potential of the cfa gene to boost cell growth and production even in heterologous strains under stress conditions. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) strains are distinct from general Staphylococcus strains with respect to the composition of the membrane, ability to form a thicker biofilm, and, importantly, ability to modify the target of antibiotics to evade their activity. The agr gene is an accessory global regulator of gram-positive bacteria that governs virulence or resistant mechanisms and therefore an important target for the control of resistant strains. However, the mechanism by which agr impacts resistance to β-lactam antibiotics remains unclear. In the present study, we found the Δagr mutant strain having higher resistance to high concentrations of β-lactam antibiotics such as oxacillin and ampicillin. To determine the influence of variation in the microenvironment of cells between the parental and mutant strains, fatty acid analysis of the supernatant, total lipids, and phospholipid fatty acids were compared. The Δagr mutant strain tended to produce fewer fatty acids and retained lower amounts of C16, C18 fatty acids in the supernatant. Phospholipid analysis showed a dramatic increase in the hydrophobic longer-chain fatty acids in the membrane. To target membrane, we applied several surfactants and found that sorbitan monolaurate (Span20) had a synergistic effect with oxacillin by decreasing biofilm formation and growth. These findings indicate that agr deletion allows for MRSA to resist antibiotics via several changes including constant expression of mecA, fatty acid metabolism, and biofilm thickening. [ABSTRACT FROM AUTHOR]

Naturally degradable bioplastic polyhydroxyalkanoate (PHA) is a promising biopolymer and its physical properties could be changed by introducing of different monomers such as 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx). To produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV)) including a high fraction of hydroxyvalerate, we introduced ctfAB into engineered Escherichia coli YJ200 possessing a pLW487 vector containing bktB, phaB, and phaC under control of the trc promoter. To enhance the HV fraction of P(3HB-co-3HV), the optimal concentrations of propionate, which acts as a precursor of 3HV and isopropyl β-D-1-thiogalactopyranoside, were determined and found to be 0.1 mM and 0.3%, respectively. Under the optimized conditions, E. coli, YJ201 produced P(3HB-co-3HV) containing a large amount of 3HV. Comparison with other CoA transferases showed that CtfAB produced relatively lower molecular weight copolymers. This demonstrates the necessity of identifying additional different CoA transferases, because CoA transferase can affect both the monomer fraction and molecular weight of polymers. [ABSTRACT FROM AUTHOR]

Bioconversion of recalcitrant keratinous biomass is one of the greatest ways to utilize products of feather hydrolysis and recycle them into bionetwork. Present study revealed 87% degradation of poultry feathers within 48 h in a constructed bioreactor using Chryseobacterium sp. RBT. The resulting feather hydrolysate (FH) was rich in soluble protein (3.56 ± 0.18 mg/ml), amino acids (3.83 ± 0.20 mg/ml), and macro and micro nutrients like N (8.0302%), P (0.3876%), K (0.5532%), Cu (0.0684%), Mg (0.8078%), Mn (0.2001%), Ca (0.4832%), Zn (0.0442%), and Fe (0.0330%). HPTLC analysis of FH revealed presence of tryptophan, cysteine, methionine, phenylalanine, glycine, valine, tyrosine, lysine, leucine, and serine as the primary amino acids. Field studies were conducted to apply FH as the bioenhancer to commercially important crops like brinjal and chilli through root drenching (20%, v/v). FH showed positive impact on the growth and development of plants along with early flowering and improved crop yield. In addition, nutritional quality of brinjal and chilli in terms of protein, amino acids, reducing sugars, phenolics, flavonoids, and antioxidant was elevated. Therefore, promotion and utility of by-products generated in feather degradation would be an effective strategy focusing on sustainable agricultural practices and problems associated with the waste management. [ABSTRACT FROM AUTHOR]

Itaconic acid is an important organic acid and a major component of various polymers. It is used in resins, superabsorbent polymers, and substitutes for petrochemicalbased monomers such as acrylic and methacrylic acids. Itaconic acid is primarily produced by the fungus Aspergillus terreus, which yields a high titer with albeit long fermentation period and by-products. In our previous study, Escherichia coli JY001 was reported to produce itaconic acid using citric acid in whole-cell reaction resulting in higher itaconic acid productivity with less by-products formation. The present study aimed to increase whole-cell enzyme stability and reusability, via immobilization of E. coli JY001 using barium-alginate beads. We optimized the cations, temperature, pH, alginate, BaCl2 concentration, cell density per bead, and CTAB content to improve transfer rate of substrates and products. Under the optimized conditions, immobilized whole cells were stable for four repeated cycles of itaconic acid production. The present results would strengthen the basis for a continuous itaconic acid production. [ABSTRACT FROM AUTHOR]

In the present study, salt-tolerant strains, Dietzia sp. HRJ2, Corynebacterium variabile HRJ4, Dietzia cinnamea HRJ5 and Bacillus tequilensis HRJ6 were isolated from the Dagang oil field, China. These strains degraded n-alkanes and polycyclic aromatic hydrocarbons (PAHs) aerobically from heavy crude oil (HCO) in an experiment at 37 °C and 140 rpm. The GC/MS investigation for degradation of different chain lengths of n-alkanes (C8-C40) by individual strains showed the highest degradation of C8-C19 (HRJ5), C20-C30 (HRJ4) and C31-C40 (HRJ5), respectively. Moreover, degradation of 16 PAHs with individual strains demonstrated that the bicyclic and pentacyclic aromatic hydrocarbons (AHs) were mostly degraded by HRJ5, tricyclic and tetracyclic AHs by HRJ6 and hexacyclic AHs by HRJ2. However, the highest degradation of total petroleum hydrocarbons (TPHs), total saturated hydrocarbons (TSH), total aromatic hydrocarbons (TAH), n-alkanes (C8-C40) and 16 PAHs was achieved by a four-membered consortium (HRJ2 + 4 + 5 + 6) within 12 days, with the predominance of HRJ4 and HRJ6 strains which was confirmed by denaturing gradient gel electrophoresis. The abundance of alkB and nah genes responsible for catabolism of n-alkanes and PAHs was quantified using the qPCR. Maximum copy numbers of genes were observed in HRJ2 + 4 + 5 + 6 consortium (gene copies l) 2.53 × 10 ( alkB) and 3.47 × 10 ( nah) at 12 days, which corresponded to higher degradation rates of petroleum hydrocarbons. The superoxide dismutase (SOD) (total SOD (T-SOD), CuZn-SOD), catalase (CAT) and ascorbate peroxidase (APX) activities in Allium sativum and Triticum aestivum were lower in the HRJ2 + 4 + 5 + 6-treated HCO as compared to the plantlets exposed directly to HCO. The present results revealed the effective degradation of HCO-contaminated saline medium using the microbial consortium having greater metabolic diversity. [ABSTRACT FROM AUTHOR]

Feather waste is a promising protein biomass available as by-product from poultry processing was found to be rich in peptides, amino acids, and minerals like nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, zinc, and copper. Soil and foliar application of these products, besides representing a sustainable solution to the problem of feather disposal, may also represent an effective strategy to tackle the environmental effluence. As a consequence, they were also found to be very attractive in elevating the protein, amino acids, reducing sugar, total chlorophyll, and proline content of plants. On the other side, fertilizing effect enhanced the antioxidant potential of banana fruit which was assessed using 2, 2-diphenyl-1-picrylhydrazyl, ferric reducing/antioxidant power, and N, N-dimethyl- p-phenylendiamine. This was associated with considerably higher antioxidant contents like total phenolics and flavonoids. Therefore, the application of this organic amendment could promote and improve the agro-ecosystem, human health; soil biological activities, and at the same time enhance the production of plant or products rich in bioactive substances. [ABSTRACT FROM AUTHOR]

In this report a textile azo dye Remazol orange was degraded and detoxified by bacterium Pseudomonas aeruginosa BCH in plain distilled water. This bacterial decolorization performance was found to be pH and temperature dependent with maximum decolorization observed at pH 8 and temperature 30 °C. Bacterium tolerated higher dye concentrations up to 400 mg l. Effect of initial cell mass showed that higher cell mass concentration can accelerate decolorization process with maximum of 92 % decolorization observed at 2.5 g l cell mass within 6.5 h. Effect of various metal ions showed Mn has inducing effect whereas Zn strongly inhibited the decolorization process at 5 mM concentration. Analysis of biodegradation products carried out with UV-vis spectroscopy, HPTLC and FTIR confirmed the decolorization and degradation of Remazol orange. Possible route for the degradation of dye was proposed based on GC-MS analysis. During toxicological scrutiny in Allium cepa root cells, induction in the activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX) and inhibition of catalase (CAT) along with raised levels of lipid peroxidation and protein oxidation in dye treated samples were detected which conclusively indicated the generation of oxidative stress. Less toxic nature of the dye degraded products was observed after bacterial treatment. [ABSTRACT FROM AUTHOR]

Research to alter crops for their better performance involving modern technology is underway in numerous plants, and achievements in transgenic plants are impacting crop improvements in unparalleled ways. Striking progress has been made using genetic engineering technology over the past two decades in manipulating genes from diverse and exotic sources, and inserting them into crop plants for inducing desirable characteristics. RNA interference (RNAi) has recently been identified as a natural mechanism for regulation of gene expression in all higher organisms from plants to humans and promises greater accuracy and precision to plant improvement. The expression of any gene can be down-regulated in a highly explicit manner exclusive of affecting the expression of any other gene by using RNAi technologies. Additional research in this field has been focused on a number of other areas including microRNAs, hairpin RNA, and promoter methylation. Manipulating new RNAi pathways, which generate small RNA molecules to amend gene expression in crops, can produce new quality traits and having better potentiality of protection against abiotic and biotic stresses. Nutritional improvement, change in morphology, or enhanced secondary metabolite synthesis are some of the other advantages of RNAi technology. In addition to its roles in regulating gene expression, RNAi is also used as a natural defense mechanism against molecular parasites such as jumping genes and viral genetic elements that affect genome stability. Even though much advancement has been made on the field of RNAi over the preceding few years, the full prospective of RNAi for crop improvement remains to be fully realized. The intricacy of RNAi pathway, the molecular machineries, and how it relates to plant development are still to be explained. [ABSTRACT FROM AUTHOR]