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The anaerobic baffled reactor (ABR) is a promising solution for decentralized wastewater treatment due to its low operation cost as compared to the activated sludge process, but it requires comparatively higher hydraulic retention time (HRT). This ultimately increases land requirement, capital and construction cost of treatment plant. This study investigates performance of ABR using polyvinyl chloride (PVC) corrugated pipe as carrier media to improve biomass retention capacity and treatment performance of reactor with the aim to reduce HRT. Comparative performance of two ABRs with and without carrier media was analyzed under mesophilic conditions (35 ± 1 °C) for organics and total suspended solids (TSS) removal at HRTs of 24, 18, 12, 8, 6 and 4 h. Results showed that at HRTs of 24–08 h, the organics removal performance of the carrier anaerobic baffled reactor (CABR) was better than ABR and was in the range of 77–81% for CABR as compared to 64–70% for ABR. However, on further decrease in HRT to 6 h, CABR sustained the treatment with organics removal of 80%, while ABR performance reduced to 58%, creating a performance difference of 38%. Average total suspended solids (TSS) removal was in the range of 76–83% at all HRTs for both reactors. Therefore, this study identified CABR with PVC carrier media as an effective low-HRT reactor for organics and SS removal with less land area requirement.

Navigating novel biological strategies to mitigate bacterial biofilms have great worth to combat bacterial infections. Bacterial infections caused by the biofilm forming bacteria are 1000 times more resistant to antibiotics than the planktonic bacteria. Among the known bacterial infections, more than 70 % involve biofilms which severely complicates treatment options. Biofilm formation is mainly regulated by the Quorum sensing (QS) mechanism. Interference with the QS system by the quorum quenching (QQ) enzyme is a potent strategy to mitigate biofilm. In this study, bacterial strains with QQ activity were identified and their anti-biofilm potential was investigated against Multidrug Resistant (MDR) Pseudomonas aeruginosa. Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136-based bioassays were used to confirm the degradation of different Acyl Homoserine Lactones (AHLs) by QQ isolates. The 16S rRNA gene sequencing of the isolated strains identified them as Bacillus cereus strain QSP03, B. subtilis strain QSP10, Pseudomonas putida strain QQ3 and P. aeruginosa strain QSP01. Biofilm mitigation potential of QQ isolates was tested against MDR P. aeruginosa and the results suggested that 50% biofilm reduction was observed by QQ3 and QSP01 strains, and around 60% reduction by QSP10 and QSP03 bacterial isolates. The presence of AHL degrading enzymes, lactonases and acylases, was confirmed by PCR based screening and sequencing of the already annotated genes aiiA, pvdQ and quiP. Altogether, these results exhibit that QQ bacterial strains or their products could be useful to control biofilm formation in Pseudomonas aeruginosa.

Chromium (VI) a highly toxic metal, a major constituent of industrial waste. It is continuously release in soil and water, causes environmental and health related issues, which is increasing public concern in developing countries like Pakistan. The basic aim of this study was isolation and screening of chromium resistant bacteria from industrial waste collected from Korangi and Lyari, Karachi (24˚52ʹ46.0ʺN 66˚59ʹ25.7ʺE and 24˚48ʹ37.5ʺN 67˚06ʹ52.6ʺE). Among total of 53 isolated strains, seven bacterial strains were selected through selective enrichment and identified on the basis of morphological and biochemical characteristics. These strains were designated as S11, S13, S17, S18, S30, S35 and S48, resistance was determined against varying concentrations of chromium (100-1500 mg/l). Two bacterial strains S35 and S48 showed maximum resistance to chromium (1600 mg/l). Bacterial strains S35 and S48 were identified through 16S rRNA sequence and showed 99% similarity to Bacillus paranthracis and Bacillus paramycoides. Furthermore, growth condition including temperature and pH were optimized for both bacterial strains, showed maximum growth at temperature 30ºC and at optimum pH 7.5 and 6.5 respectively. It is concluded that indigenous bacterial strains isolated from metal contaminated industrial effluent use their innate ability to transform toxic heavy metals to less or nontoxic form and can offer an effective tool for monitoring heavy metal contamination in the environment. Resumo O cromo (VI), metal altamente tóxico, é um dos principais constituintes dos resíduos industriais. É liberado no solo e na água, causa problemas ambientais e de saúde de crescente preocupação pública em países em desenvolvimento como o Paquistão. O objetivo básico deste estudo foi o isolamento e a triagem de bactérias resistentes ao cromo de resíduos industriais coletados em Korangi e Lyari, Karachi (24˚52’46,0”N 66˚59’25,7”E e 24˚48’37,5”N 67˚06’52,6”E). Do total de 53 cepas isoladas, sete cepas bacterianas foram selecionadas por enriquecimento seletivo e identificadas com base em características morfológicas e bioquímicas. Essas cepas foram designadas como S11, S13, S17, S18, S30, S35 e S48, apresentaram alta resistência aos metais contra concentrações variáveis (100-1500 mg / l) de cromo. Já as cepas S35 e S48 foram identificadas por meio da sequência 16S rRNA e apresentaram 99% de similaridade com Bacillus paranthracis e Bacillus paramycoides. Além disso, as condições de crescimento incluindo temperatura e pH foram otimizadas e ambas as cepas bacterianas apresentaram crescimento máximo na temperatura de 30 ºC, enquanto seu pH ótimo foi observado em 7,5 e 6,5, respectivamente. Conclui-se que o potencial de resistência dessas bactérias resistentes ao cromo pode ser efetivamente utilizado na remoção de cromo de efluentes industriais contaminados. Técnicas de base biológica usando bactérias ajudarão a fornecer métodos mais baratos e ecológicos de remoção, recuperação e desintoxicação de cromo.

In this study, the antifungal, antioxidant, enzyme inhibitory (α-amylase), phytochemical and cytotoxicity profile of Jatropha curcas seed oil and de-oiled seed cake extracts was determined. The antifungal activities were investigated against different phytopathogenic fungi including Colletotrichum coccodes, Pythium ultimum, Phytophthora capsici, Rhizoctonia solani, Bipolaris oryzae and Fusarium fujikuroi. Methanolic extract was found to be highly fungicidal as compared to aqueous extract, n-hexane extract and seed oil, against P. capsici and F. fujikuroi. Methanolic extract was also found to possess significantly higher antioxidant potential (p

Antimicrobial activities of deoiled seed kernel (mechanically pressed), fruit coat and seed coat of Jatropha curcas Linn. collected from two regions (Bannu and Peshawar) of Pakistan were investigated. The antimicrobial activities were carried out against Klebsiella pneumoniae (ATCC 43816), Escherichia coli (ATCC 10536), Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633) and two clinical fungal isolates Aspergillus fumigatus and Candida albicans using agar well diffusion method. The antibacterial activities of Peshawar sample were found to be higher than Bannu, against selected strains. While antifungal activities of both samples were similar. Highest zone of inhibition 31.5 ± 0.7 mm was exhibited by n-hexane extract of deoiled seed kernel of Peshawar sample against Bacillus subtilis (ATCC 6633). The minimum inhibitory concentration of ethanolic extracts of deoiled seed kernel and seed coat of Peshawar sample was 31.25 - 25 mg/ml. Whereas, minimum inhibitory concentration of ethanolic and n-hexane extracts of Bannu sample was 62.5 - 125 mg/ml. The results suggested that antimicrobial potential of J. curcas Linn. varied with geographical distribution. The investigation of different varieties of medicinal plants belonging to the same species will greatly enhance the chances of best pharmaceuticals discovery. Bangladesh J. Bot. 50(2): 219-226, 2021 (June)

The environmental release of mercury is continuously increasing with high degree of mobility, transformation and amplified toxicity. Improving remediation strategies is becoming increasingly important to achieve more stringent environmental safety standards. This study develops a laboratory-scale reactor for bioremediation of aqueous mercury using a biofilm-producing bacterial strain, KBH10, isolated from mercury-polluted soil. The strain was found resistant to 80 mg/L of HgCl2 and identified as Bacillus nealsonii via 16S rRNA gene sequence analysis. The strain KBH10 was characterized for optimum growth parameters and its mercury biotransformation potential was validated through mercuric reductase assay. A packed-bed column bioreactor was designed for biofilm-mediated mercury removal from artificially contaminated water and residual mercury was estimated. Strain KBH10 could grow at a range of temperature (20–50 °C) and pH (6.0–9.0) with optimum temperature established at 30 °C and pH 7.0. The optimum mercuric reductase activity (77.8 ± 1.7 U/mg) was reported at 30 °C and was stable at a temperature range of 20–50 °C. The residual mercury analysis of artificially contaminated water indicated 60.6 ± 1.5% reduction in mercury content within 5 h of exposure. This regenerative process of biofilm-mediated mercury removal in a packed-bed column bioreactor can provide new insight into its potential use in mercury bioremediation. HIGHLIGHTS Bioaccumulation of aqueous mercury in the food web is a matter of grave concern.; Enzymatic reduction of mercury by resistant bacteria reduces its potential toxicity.; Bacillus nealsonii possess the inbuilt mechanisms of necessary adaptation.; Mercury content was reduced up to 60.6 ± 1.5% within 5 h of exposure in packed-bed bioreactor.; Biofilm-mediated mercury remediation is efficient, regenerative and cost-effective.

A Martelella endophytica (M. endophytica) strain YC6887 was previously isolated from the roots of a halophyte, Rosa rugosa, which was sequenced and characterized. The genomic and proteomic analysis showed a carbohydrate-degrading enzyme, endoglucanase Cel5A which was further characterized. The protein analysis revealed that this endoglucanase belongs to glycosidic hydrolase family 5 (GH5) with catalytic domain. This gene encodes 349-residue polypeptide and shows closest similarity with cellulases of other Martelella species. The protein was purified to homogeneity and shown that it was a 39 kDa protein. The purified recombinant Cel5A endoglucanase exhibited maximum activity at 50 °C and pH 4.5. The enzyme was salt tolerant and retained more than 50% residual activity up to 15% NaCl. The homology model structure of Cel5A displayed that it is stable and compact protein structure consisting of eleven α-helical structures and eight β-sheets. According to the predicted ligand binding site after superimposition with Pseudomonas stutzeri endoglucanase Cel5A (PDB ID: 4LX4), it consisted of five amino acid Asn157, Tyr116, Glu158, Glu270 and Trp303 that may be the expected active site of Cel5A from YC6887. This presented that our strain M. endophytica YC6887 that produces cellulase partially degrade the insoluble polysaccharides into reducing sugars.

The excesssive use of agrochemicals to fulfill the high demand of agricultural products has been imposing numerous negative impacts on the environment for decades worldwide. Untreated wastewater with high chemical load and unutilized nutrients of fertilizers and pesticides released from agricultural farms results in contamination and intoxication of clean water bodies. Giant duckweed specifically Spirodela polyrhiza specie has shown the potential to efficiently uptake nutrients from nutrient rich waters thus, it can be employed cost-effective approach for phytoremediation of agricultural runoff. S. polyrhiza biomass also serves as an alternative feedstock for the production of biofuels which is another precedence of using this method. In this study, the potential of S. polyrhiza for removing nitrogen and phosphates from the agricultural runoff was determined by growing it in the agricultural runoff under lab conditions. Upto 70% and 78% removal of nitrogen and phosphates respectively was achieved during the treatment of agricultural runoff by Spirodela polyrhiza. The starch content of Spirodela polyrhiza was elevated 58% during 10–12 days of nutrient starvation at the end of the agricultural runoff treatment process. The biomass obtained was pretreated with dilute acid that liberated 96.4% glucose from the starch-rich biomass. This glucose was used as a substrate for the fermentation process carried out by Saccharomyces cerevisiae QG1 MK788210 yeast strain which yielded 99% volumetric conversion of glucose into bioethanol. The remaining fermentation vinnasse was anaerobically digested and 589 Nml/g VS biogas yield was obtained. To the best of our knowledge this is the first study that develops a lab-scale bioprocess in terms of integrated wastewater derived S. polyrhiza biorefinery.

High-altitude cold habitats of the Karakoram are rarely explored for their bacterial community characterization and metabolite productions. In the present study, bacterial communities in ice, water, and sediments of Batura Glacier were investigated using culture-dependent and culture-independent methods. Twenty-seven cold-adapted bacterial strains (mostly psychrotrophic) were isolated using R2A, Tryptic Soy Agar (TSA), and Luria-Bertani (LB) media, at 4 °C and 15 °C. Most of the isolates exhibited growth at a wide range of temperature (4–35 °C), pH (5–12), and salinity (1–6%). Among the bacterial isolates, 52% were identified as Gram-positive and the remaining 48% represented as Gram-negative. The results of phylogenetic analysis indicated that all the culturable bacteria belonged to 3 major phylogenetic groups, i.e., Actinobacteria (48%), Bacteroidetes (26%), and Proteobacteria (22%), while Flavobacterium (26%), Arthrobacter (22%), and Pseudomonas (19%) were represented as the dominant genera. Similarly, Illumina amplicon sequencing of 16S rRNA genes after PCR amplification of DNA from the whole community revealed dominance of the same phylogenetic groups, Proteobacteria, Actinobacteria, and Bacteroidetes, while Arthrobacter, Mycoplana, Ochrobactrum, Kaistobacter, Janthinobacterium, and Flavobacterium were found as the dominant genera. Among the culturable isolates, 70% demonstrated activity for cellulases, 48% lipases, 41% proteases, 41% DNases, and only 7% for amylases. Most of the glacial isolates demonstrated antimicrobial activity against other microorganisms including the multiple-drug-resistant strains of Candida albicans, Klebsiella pneumoniae, Acinetobacter sp., and Bacillus sp. 67% of Gram-negative while 46% of Gram-positive glacial bacteria were resistant to trimethoprim/sulfamethoxazole. Resistance against methicillin and vancomycin among the Gram-positive isolates was 23% and 15%, respectively, while 11% of the Gram-negative isolates exhibited resistance against both colistin sulfate and nalidixic acid.

The combustion of fossil fuels is accompanied with a number of alarming problems such as fossil fuel depletion, increase in their prices, and emission of greenhouse gases. Thus, the need for the alternative renewable biofuels was increased to replace non-renewable fossil fuels. The sustainable use of non-edible feedstocks and waste for production of biofuels is a potential approach for reducing dependency on fossil fuels and mitigating environmental pollution. In the current study, the effects of carbon to nitrogen (C/N) ratios on methane yield during anaerobic co-digestion of Jatropha curcas de-oiled seed kernel and mango peels were evaluated in continuous reactors. The biogas potential and effects of acid pretreatment on J. curcas fruit were also evaluated during anaerobic batch digestion. The methane yield of co-digested mango peels and seed kernel (1:4 weight ratio based on volatile solids) was 61%, 50%, 36%, and 25% higher compared with the methane yields of mango peels, seed kernel, mango peels/seed kernel (2:1 w/w), and mango peels/seed kernel (1:1 w/w), respectively. The methane yields of the co-digestion of mango peels and seed kernel at 1:4, 1:1, and 2:1 ratios were 52%, 39%, and 32% of the theoretical yields, respectively, illustrating the importance of adjusting C/N ratio with the right amounts of co-substrate. The biogas yield of pretreated fruit coat was 7%, 22%, 34%, 50%, and 74% higher than that of the seed kernel, fruit coat (non-pretreated), de-oiled kernel plus seed coat (pretreated) (1.7:1, by weight), seed coat (pretreated), and seed coat (non-pretreated), respectively. Additionally, pretreatment of fruit coat and seed coat resulted in 22% and 47% higher biogas yields compared with their non-pretreated counterparts. This study revealed key substrate selection and pretreatment methods for increasing methane production from common seed oil production and agricultural wastes.

A radio-resistant bacterium labeled as strain TMC-6 was isolated from Thal desert, Pakistan and identified through 16S rRNA gene sequencing as Bacillus indicus strain TMC-6 (MN721293). The isolate was found to be resistant to UV radiation dose of 6.780 × 103 J/m2 and showed 50% survivability to mitomycin C (6 μg/ml) and H2O2 (30 mM). The bacterium showed yellowish orange coloration when grown on tryptone yeast glucose (TGY) medium. The cellular metabolite was extracted in methanol and purified through solid phase extraction with C18 column cartridge. The compound was characterized through UV/Visible spectrophotometry, Fourier Transform Infra-Red (FT-IR) spectroscopy and Liquid Chromatography Mass Spectrometry (LC–MS). The LC–MS analysis of the compound revealed a molar mass of 769 [m/z]− that matched the chemical formula C34H42O20 and identified as a glycosylated flavonoid xanthorhamnin. The compound showed significant antioxidant (77.05%) and metal chelation (79.80%) activities. Xanthorhamnin showed promising oxidative damage inhibitory actions in bovine serum albumin (65.32%) and mice liver lipids (71.61%) and prevented DNA strand breaks from oxidative stress. Cytotoxicity in brine shrimp larvae was observed when compared with mitomycin C indicating its effect toward cancerous cells. These findings concluded that xanthorhamnin from radio-resistant Bacillus indicus strain TMC-6 has high antioxidant, radioprotective, and antitumor properties against UV-mediated oxidative damages.

This study aims to determine UV-B resistance and to investigate computational analysis and antioxidant potential of methoxy-flavones of Micromonospora aurantiaca TMC-15 isolated from Thal Desert, Pakistan. The cellular extract was purified through solid phase extraction and UV-Vis spectrum analysis indicated absorption peaks at λmax 250 nm, 343 nm, and 380 nm that revealed the presence of methoxy-flavones named eupatilin and 5-hydroxyauranetin. The flavones were evaluated for their antioxidant as well as protein and lipid peroxidation inhibition potential using di(phenyl)-(2,4,6-trinitrophenyl) iminoazanium (DPPH), 2,4-dinitrophenyl hydrazine (DNPH), and thiobarbituric acid reactive substances (TBARS) assays, respectively. The methoxy-flavones were further studied for their docking affinity and interaction dynamics to determine their structural and energetic properties at atomic level. The antioxidant potential, protein and lipid oxidation inhibition and DNA damage preventive abilities were correlated as predicted by computational analysis. The eupatilin and 5-hydroxyauranetin binding potential to their targeted proteins 1N8Q and 1OG5 is -4.1 and -7.5 kcal/mol, respectively. Moreover, the eupatiline and 5-hydroxyauranetin complexes illustrate van der Waals contacts and strong hydrogen bonds to their respective enzymes target. Both in-vitro studies and computational analysis results revealed that methoxy-flavones of Micromonospora aurantiaca TMC-15 can be used against radiation mediated oxidative damages due to its kosmotrophic nature. The demonstration of good antioxidant activities not only protect DNA but also protein and lipid oxidation and therefore could be a good candidate in radio-protective drugs and as sunscreen due to its kosmotropic nature.

Spirodela polyrhiza is a fast-growing hydrophyte with the ability to attain high starch and high biomass yield which makes it an excellent alternative feedstock for the production of biofuels. In this study, Spirodela was given nutrient stress to enhance its starch content from 21 to 80%. The plant biomass with high starch was pretreated with dilute acid for conversion of starch to glucose which was fermented with indigenously isolated and optimized yeast strain and yielded 99.8% of theoretical ethanol yield. The fermentation vinasse was anaerobically digested, and 0.88 NL/g VS yield of biogas was obtained. Further, output energy analysis of bioethanol, biogas, and both bioethanol and biogas sequentially produced from Spirodela was carried out, which showed that highest amount of energy is produced in the process where high starch containing Spirodela plant biomass was used for the production of biomethane only. The results obtained showed that high starch Spirodela is best used in terms of energy when it is anaerobically digested for production of biogas only. To the best of our knowledge, this study is the first one which attempts to practically depict that this feedstock can be used in a sequential process to produce the two biofuel variants by using the same batch of feedstock. Further, this study for the first time evaluates the energy output potential of biofuels produced from Spirodela. It was interesting to see that in terms of energy output, duckweed has more potential for biogas production than that of ethanol, while many researchers have focused the production of ethanol only from Spirodela.

To utilize wastes and residues sustainably and excellently, there is a need to fend for efficient methods and resources for biogas production. Use of poultry waste for biogas production represents one of the most important routes toward reaching global renewable energy targets. The current study involves microbial pretreatment of chicken feather waste, followed by its co-digestion with rice husk and green grocery waste in batch and continuous reactors, respectively. Microbial pretreatment of chicken feathers by keratinase secreting Pseudomonas aeruginosa was an effective and eco-friendly approach to make its recalcitrant structure available as a raw substrate for biogas production. The current study also addressed the enhancement and stability of anaerobic digestion by co-digestion. Results demonstrated that biogas production was increased by microbial pretreatment of chicken feathers and that the percentage increase in biogas yield was 1.1% in microbialy pretreated feathers compared to mono-digestion (non-pretreated feathers) in batch fermentation. The highest yield of biogas was obtained in a batch reactor having co-digestion of pretreated rice husk and microbial pretreated chicken feathers. The co-digestion of chicken feathers hydrolysate with green grocery waste in continuous fermentation mode has also enhanced the biogas yield as compared to average of mono-digestion (chicken feather hydrolysate and green grocery waste) and, therefore, improve the efficiency of the overall process.

Xylanases from microbial sources assume basic jobs in an assortment of industrial applications as a biocatalyst, and its applications generally require immobilization on supports to upgrade their stability. Enzyme immobilization is a thrilling decision to show signs of improved strength of enzymatic procedures. In this work, two sorts of polymeric backings (agar-agar and calcium alginate) are utilized to immobilize β-1,4-xylanase from Thermomyces lanuginosus C9 by entrapment, and afterward, biochemical properties of the entangled enzymes were performed. To create immobilized catalyst beads centralization of 4% agar while mix of sodium alginate 5% and calcium chloride 0.4 M was seen as ideal. Ideal reaction time for agar and calcium alginate immobilized protein increments from 10 to 25 and 30 min, separately. The incubation temperature expanded from 70°C to 75°C for agar however stayed unaltered for calcium alginate. The pH profile of free and immobilized xylanase was generally equal in both cases. Be that as it may, both the strategies changed the active boundaries of immobilized β-1,4-xylanase rather than free protein. High sub-atomic load of xylan limits dispersion which brings down the Vmax estimation of immobilized protein while Km value expanded. In contrast with agar-agar, protein immobilized inside calcium alginate display wide thermal stability and kept up 86.6% of its underlying activity at 80°C up to 150 min. Be that as it may, biotechnological portrayal demonstrated that the catalyst reusability was the most surprising discovery, predominantly of agar-agar immobilized xylanase, which held 31% activity after 7 cycles. These outcomes prove the biotechnical and monetary advantages of immobilization which help in an assortment of industrial applications.

The current study was aimed to enzymatically modify maize flour by using amylase and pullulanase in combination for increasing the yield of resistant starch type III (EM-RSIII). The enzymatic treatment imparts unique desired physicochemical properties to the maize flour including resistant starch content, amylose content, milk, oil, and water interaction ability. The sensory analysis was performed by distributing questioners among individual and results were interpreted by 5-point hedonic scale. Result indicated an increase in the stability, amylose content, and milk absorption capacity of maize flour, while a decrease in swelling power, water absorption, and oil absorption capacity. The enzymatic treated maize flour led to the transformation of amorphous native structure into a crystalline structure which was confirmed by light microscopy, scanning electron microscopy, X-ray diffractograms analysis, and in vitro digestibility of EM-RSIII. The EM-RSIII rich maize flour was used in cookies preparation and a significant difference in palatability and color parameters was observed. Crispiness and texture of EM-RSIII containing cookies was increased due to its low swelling power, water absorption, and oil absorption capacity. The sensory analysis showed that consumers depicted the highest acceptability of EM-RSIII supplemented cookies specifically for its appearance, sharp aroma, texture and accepted as nutritionally important food item for consumers.

Metallotolerant fungi are known for their ability to adapt to high concentrations of heavy metals by producing extracellular metabolites. We isolated an acid-producing filamentous fungus, designate...

The depletion of nonrenewable fossil fuels and the rise in their prices depicts that there is a need to fend for alternative fuel resources. Biofuels are one of these renewable alternative options. Among biofuels, bioethanol is one of the most widely used transportation fuels around the world. However, currently, bioethanol is produced from food crops, which is raising food versus fuel feud. Spirodela polyrhiza is one of the novel feedstock that can be used to produce bioethanol at large scale without causing any food and fuel competition. This study involves the collection of S. polyrhiza from a local pond and establishment of its growth in Hoagland growth media. The plant was then given nutrient starvation stress to enhance its starch content by 78%. The high-starch-containing plant biomass was acid-pretreated, and 99.3% starch-to-glucose conversion was achieved. In order to ferment plant sugars, yeast strain Saccharomyces cerevisiae QG1 MK788210 was indigenously isolated and statistically optimized using Plackett–Burman and central composite design to achieve high ethanol yield. The fermentation of plant sugar by Saccharomyces cerevisiae QG1 MK788210 resulted in 100% ethanol yield thus successfully achieving complete conversion of S. polyrhiza starch to bioethanol. The study conducted demonstrates effective optimization of indigenously isolated yeast strain S. cerevisiae QG1 MK788210 to deliver high ethanol yield from S. polyrhiza. Further, this study has been successful in delivering a process for complete conversion of starch from nutrient-starved S. polyrhiza biomass into bioethanol.

A xylanase-producing bacterium Bacillus pumilus K22 was isolated from hot spring located in Manghopir area, Karachi, Pakistan. The enzyme was purified to homogeneity by acetone precipitatio...

The depletion of non-renewable fossil fuels and a surge in their prices have led researchers to seek alternative, renewable energy sources; among them, biodiesel is a good option, especially in the...

Polysaccharides including resistant starch are categorized as dietary fiber and are used as an important prebiotic. Similar to soluble fibers, resistant starch also has a number of physiological effects that have been shown to be beneficial for health. Starch hydrolyzing enzymes, most importantly amylases, play essential roles in the production of resistant starch. This study aimed to develop α-amylase-treated maize flour with slow digestibility and unique physicochemical characteristics compared to native maize flour. In the current study, resistant starch type III from maize flour was prepared using α-amylase obtained from indigenously isolated Bacillus licheniformis. The α-amylase gene from B. licheniformis was amplified and cloned into the pET-24(a) vector, expressed in E. coli BL21 (DE3) cells and purified by metal ion affinity chromatography. The purified enzyme enhanced the yield of resistant starch 16-fold in maize flour. Scanning electron microscopy revealed that the granular structure of maize flour was disrupted into a dense network with irregular structure, and X-ray diffractograms confirmed the transformation from an amorphous to a crystalline structure upon α-amylase treatment. Thermogravimetric analysis revealed increased amylose content of α-amylase-treated maize flour. Moreover, α-amylase-treated maize flour resulted in a significant enhancement of the desired properties of maize flour, such as resistant starch content, amylose, milk absorption capacity, and iodine and fatty acid complexing ability, and a reduction in swelling power, water binding, oil absorption capacity, and in vitro digestibility compared to untreated maize flour. Resistant starch type III showed low digestibility and increased complexing ability with iodine and fatty acid and therefore could be a safe and beneficial alternative as a coating material for the delivery of active, sensitive ingredients to the colon.

Biodiesel is one of the best alternative to depleting fossil fuels for transport sector. However, biodiesel production via lipase mediated transesterification has limitation of high costing microbial enzymes. In order to overcome this limitation, a process of sequential treatment of oil industry wastewater using isolated lipolytic bacterial strains and biodiesel production from non-edible plant oils was studied. In this study, efficient lipase producing bacteria were isolated and evaluated for production of biodiesel from mustard, soybean, jatropha and taramira oils utilizing methanol for the transesterification of oils and bioremediation. Selected strains were then identified, using 16s rRNA sequencing. Further, Bacillus subtilis strain Q1 KX712301 was optimized for biodiesel production from non-edible taramira oil via Plackett–Burman and central composite design. Highest volumetric yield of biodiesel obtained was 102% at optimized parameters. Finally, a sequential bioremediation of vegetable oil contaminated wastewater and then microbial production of biodiesel from non-edible taramira oil was carried out using efficient lipase producer B. subtilis strain Q1 at optimized conditions. During sequential process, complete chemical oxigen demand reduction of oil containing wastewater and theoretical volumetric yield of biodiesel was achieved. Gas chromatography/mass spectrometry chromatogram revealed that the total fatty acid methyl ester content of the produced biodiesel was >98% which is in accordance with the biodiesel quality standards specified by both ASTM and EU-14103.

BACKGROUND: The present study compared the performance and capability of thermophilic–mesophilic, temperature‐phased anaerobic digestion (TPAD) of wastewater sludge at 45 and 55 °C in terms of rate of hydrolysis and methanogenesis at two point interval times – December and January – with operational conditions kept constant (total solid content 6.5%, solids retention time 12.5 days). RESULTS: The reduction of volatile solids (VS) was 77% at 45 °C TPAD‐1 and 72% at 55 °C TPAD‐II. The accumulation of ammonia and volatile fatty acids (VFAs; propionic acid) were observed to be below the inhibitory range (>3000 mg L⁻¹), whereas the methane (CH₄) production (45 °C, 3.55 ± 0.47 L CH₄ L⁻¹ day⁻¹; 35 °C, 1.44 ± 0.12 L CH₄ L⁻¹ day⁻¹) remained considerably higher in TPAD‐I than TPAD‐II. Furthermore, the TPAD‐II system suffered from certain degree of instability due to high level of total VFAs (6087 ± 1578 mg L⁻¹), low buffering capacity, increased level of total NH₃ (2982 ± 219 mg L⁻¹) and free NH₃ (246 ± 25 mg L⁻¹), and relatively reduced CH₄ production (1.69 ± 0.1 L L⁻¹ day). The bacterial and archaeal population of the TPADs investigated by 454 pyrosequencing and Illumina sequencing showed, in both TPAD systems, a bacterial community dominated by Firmicutes, followed by Bacteriodetes, Proteobacteria, Synergistetes and Actiniobacteria. The archaeal community was dominated by Methanimicrobia (74–84% Methanosarcina) and Methanobacteria (15–27% Methanobacterium). A progression from genus Clostridium to Coprothermobacter and Tepidanaerobacter, and Methanocarcina to Methanothermobacter and Methanobacterium was observed in TPAD‐II. CONCLUSIONS: This study proved the processes driving the dynamics of key microbial population and its correlation with hydrolytic functionality of TPAD systems. © 2019 Society of Chemical Industry

The design of actively efficient and low-toxicity formulations against virulent bacterial strains causing skin infections remains a challenging task. The aim of the present study was to develop and evaluate in vitro a hydrogel impregnated with a known plant extract for topical applications against major skin bacteria. A poly(vinyl alcohol) (PVA)/gelatin hydrogel, namely HG, was prepared by esterification following the solution casting method. The gelling process was realized by cross-linking the synthetic polymer PVA and the biopolymer gelatin in the presence of hydrochloric acid (HCl). A crude extract of Nigella sativa seeds was then encapsulated in HG, and the resulting HGE was characterized morphologically (by Scanning Electron Microscopy (SEM)), structurally (by X-ray powder diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy), behaviorally (by swelling behavior), and biologically (by the agar well diffusion method). The results of HGE were compared to HG and HG impregnated with 10% acetic acid (HGAA). SEM sections of HGE revealed a dense and porous surface, suggesting a good hydrophilicity. X-ray diffractograms indicated that HGE and HG had a similar degree of crystallinity. FTIR spectra confirmed that esterification occurred between PVA and gelatin suggesting that the amine group is involved in the intercalation of the plant extract components in HG. Further, HGE was found to be as wettable and swellable as HG, suggesting a good biocompatibility. Eventually, HGE exerted a pronounced inhibitory effect against two major skin pathogens, the Gram-negative Pseudomonas aeruginosa and the Gram-positive Staphylococcus aureus, suggesting a good extract release. Taken together, the experimental data indicated that HGE might be a promising wound dressing.