Minimal Salt Medium Research Articles

Isolation and Identification of Tannin-Degrading Bacteria From Goat Feces, Ruminal Fluid, and Rumen Gut

Tannins are toxic polyphenols present in various plants, contributing to microbial attacks and plant protection due to their astringence and bitter taste. However, high tannin inclusion in poultry diets will result in dyspepsia, hampering nutrient absorption and digestion. Interestingly, several bacteria occupying the rumen and gastrointestinal tract (GIT) of animals may tolerate tannins and degrade them by wielding tannase enzymes. The study aims to isolate and characterize potential tannin-degrading bacteria (TDB) from several ruminant specimens. The TDBs were isolated based on their tannin hydrolyzing ability on a minimal salt medium (MSM) agar complemented with 0.2% tannic acid as the sole source of carbon and energy. The maximum tannin tolerance of the isolates was characterized using increased tannin concentrations on the MSM agar plates. Furthermore, the tannase activity was also evaluated over a five-day incubation. A total of 42 tannin degraders were isolated, and 10 TDBs were chosen for further characterization based on the hydrolyzed zone produced. Molecular identification revealed the presence of Bacillus cereus (TDB536), Lysinibacillus macroides (TDB17), Acinetobacter nosocomialis (TDB18, 20, 23, 24, 30, 35), and Staphylococcus saprophyticus (TDB40). TDB17, TDB18, and TDB24 showed the highest tannic acid tolerance at 1.0%, while TDB36 and TDB40 exhibited the lowest tolerance at 0.4%. Each TDB displayed varying tannase activities, ranging from 11.56 to 42.08 U/mL over a five-day incubation period. TDB5 and TDB35 demonstrated significantly higher tannase activity on day 2 (p<0.05). Meanwhile, TDB23 and TDB24 showed the highest tannase on day 4 (p<0.05). Among the isolates, A. nosocomialis strain AE6 (TDB24) from feces exhibited the highest tannase activity (42.08 U/mL) and represented the best TDB. The isolated strains demonstrate their capabilities in reducing tannin's antinutritional effects in poultry feed.

Isolation of Monocrotophos degrading bacterial consortium from agricultural soil for in vivo analysis of pesticide degradation.

Extensive Monocrotophos (MCP) application in agricultural soils has led to its ubiquitous accumulation in the environment. Human health can be adversely affected by chronic exposure to produce and water from such areas, causing endocrine dysfunction, birth defects, blood and nervous disorders. This study investigated the possibility of detecting Monocrotophos-degrading bacteria in soil samples taken from a cotton cultivation field in a local area. We isolated a consortium that could tolerate and neutralize Monocrotophos upto a concentration of 2000 ppm. The consortium on 16S rRNA sequencing were identified as Micrococcus luteus SBR2, Rhodococcus SBR5, Bacillus aryabhattai SBR8, Ochrobactrum intermedium SBK2. Significant tolerance of individual strains in the range of 500-5000 ppm was observed when incubating them in vitro with Monocrotophos in minimal salt medium. An analysis of the degrading genes opdA, mpd, and opd revealed plasmid borne opdA and mpd in the O.intermedium strain and B.aryabhattai strain. All the strains indicated genomic opdA and mpd whereas opd was not detected in plasmid or genomic DNA. The HPLC showed no peak at 2.5min, when individual strains were incubated with Monocrotophos. The HPLC analysis of soil samples incubated with the consortium for two weeks showed complete degradation of Monocrotophos. GC-MS analysis confirmed that Monocrotophos and its solvent cyclohexamide were degraded into non-toxic compounds such as cyclotrisiloxane compounds, acetic acid, and others. This study indicates that the expression of organophosphate hydrolyzing enzymes in the consortium can greatly contribute to the neutralization of organophosphorus compounds and also serve as a bioremediation method for agricultural soils.

Indigo carmine biodegradation by endophytic Microbacterium zeae K5: Enzymatic insights, degradation mechanism, and ecotoxicity analysis

The enormous amount of colored effluent release from dying industries into fresh and marine reservoirs, causing ecotoxicity and serious health problems. Pertaining to this, the current research emphasis on the decolorization and degradation treatment of Indigo carmine (IC). The decolorization of IC with endophytic Microbacteium zeae K5, isolated from the root of the Salix purpurea plant was studied. In a minimal salt medium with shaking, full dye decolorization (400 mg/L) was achieved within a 24 h incubation period. During dye degradation, the activities of enzymes such as laccase (12.02 U/g), manganese peroxidase (4.23 U/g), and quinone dehydrogenase (0.09 U/g) were also observed. The biodegradation of IC into isatin sulfonic acid and isatin was confirmed by UV–VIS spectrophotometry and GC-MS analysis of dye samples extracted with ethyl acetate. Finally, phytotoxicity studies revealed that the IC degraded metabolites toxicity was lower than that of the parent dye compound. The current study demonstrated isolate M. zeae K5 has ability to efficiently break down IC, indicating its potential for future bioremediation uses.

Isolation and Molecular Characterization of Polyester-Degrading Bacterial Strains from Municipal Wastewater and Their Application in Microplastic Degradation in Contaminated Wastewater

Diverse synthetic polymers find their regular application in routine life and are disposed of directly into the environment through various sources. The released microplastic and microfibres from the sources creates contamination in both aquatic and terrestrial environments. When these micropollutants enter the food chain, they have adverse effects on the environment and human health. This study focuses on the application of native bacterial strains isolated for the effective degradation of polyester microfibers. The isolated bacterial strains, namely MFB 6, MFB 8, and MFB 11, tolerant to polyethylene glycol (PEG), were identified as Bacillus sp., Paenibacillus sp., and Aeromonas veronii, respectively, with NCBI gene bank accession numbers ON318306, ON318390, and PP237260. Polyester biodegradation efficiency of 10.5%, 12.6% and 8.4% was achieved by MFB 6, MFB 8 and MFB 11, respectively, after 42 days of investigation in minimal salt medium under shake flask condition. In future the application of these microorganisms will help in sustainable management of synthetic microfiber pollutants and find their suitable application in micro plastic degradation in contaminated wastewater.

Screening of Different Fungi Strains Gongronella sp. WICC F60 and Cordyceps sp. WICC F61 for Degradation of Low-Density Polyethylene

Over the past decade, polyethylene (PE) products have become increasingly important in several industries. Their biggest concerns are plastic material degradation resistance and environmental longevity. Therefore, this study aims to find fungi that are capable of degrading low-density polyethylene (LDPE) efficiently. This study uses Gongronella sp. WICC F60, and Cordyceps sp., WICC F61. The fungi were grown on potato dextrose agar for 30 days. Following that, fungal colonies were placed in potato dextrose broth for incubation. The LDPE sample was then cultured with the fungal strain in a minimum salt medium with a 10% inoculum. After 30 days of biodegradation testing, the analysis was done. These studies measured LDPE sample weight loss, pH, and fungal biomass. It was observed that the LDPE sample weight loss increased with time until the end of inclubation. Gongronella sp. WICC F60 and Cordyceps sp. WICC F61 were able to degrade LDPE plastic. Both fungi show an increase in LDPE weight loss. However, Cordyceps sp. WICC F61 shows more efficiency in LDPE degradation compared to Gongronella sp. WICC F60. The LDPE weight loss using Gongronella sp. WICC F60 was 1.07%, which is lower than Gongronella sp. WICC F60's LDPE weight reduction of 5.56%.

Improvement in Salt Tolerance Ability of Pseudomonas putida KT2440.

Pseudomonas putida KT2440 is a popular platform for bioremediation due to its robust tolerance to environmental stress and strong biodegradation capacity. Limited research on the salt tolerance of P. putida KT2440 has hindered its application. In this study, the strain KT2440 was tested to tolerate a maximum of 4% w/v NaCl cultured with minimal salts medium. Transcriptomic data in a high-salinity environment showed significant expression changes in genes in membrane components, redox processes, chemotaxis, and cellular catabolic processes. betB-encoding betaine-aldehyde dehydrogenase was identified from the transcriptome data to overexpress and enhance growth profile of the strain KT2440 in minimal salts medium containing 4% w/v NaCl. Meanwhile, screening for exogenous salt-tolerant genes revealed that the Na+/H+ antiporter EcnhaA from Escherichia coli significantly increased the growth of the strain KT2440 in 4% w/v NaCl. Then, co-expression of EcnhaA and betB (KT2440-EcnhaA-betB) increased the maximum salt tolerance of strain KT2440 to 5% w/v NaCl. Further addition of betaine and proline improved the salt tolerance of the engineered strain to 6% w/v NaCl. Finally, the engineered strain KT2440-EcnhaA-betB was able to degrade 56.70% of benzoic acid and 95.64% of protocatechuic acid in minimal salt medium containing 4% w/v NaCl in 48 h, while no biodegradation was observed in the normal strain KT2440 in the same conditions. However, the strain KT2440-EcnhaA-betB failed to degrade catechol in minimal salt medium containing 3% w/v NaCl. This study illustrated the improvement in the salt tolerance performance of Pseudomonas putida KT2440 and the feasibility of engineered strain KT2440 as a potential salt-tolerant bioremediation platform.

Brilliant green decolorization by dye decolorizing peroxidase producing bacterium, Achromobacter insolitus isolated from Forest soils of Similipal Biosphere Reserve, Odisha

Dye-decolorizing peroxidases (DyPs) are recently identified superfamily of heme-containing peroxidases which has received much attention for its potential application in dye decolourization. In the current research, six bacterial colonies (SDB1-6) showing lignolytic activity were isolated from forest soils of SBR using a minimal salt medium supplemented with alkali lignin and screened for DyP activity using brilliant green dye supplemented luria bertani agar medium. The highest DyP activity showing bacterium was identified using biochemical and 16SrRNA sequencing and was identified as Achromobacter insolitus. A. insolitus was found to be an efficient strain showing the highest DyP activity of 2.7 U/mL/ml at un-optimized condition. The RSM optimization was conducted to increase the DyP enzyme activity. A. insolitus demonstrated DyP activity of 6.20 U/mL/min with an increase of 2.29 times of enzyme activity in optimal condition of pH 7.0, temperature 25 °C, H2O2 concentration 0.1 mM, and time 24 h. The bacterium was further screened for dye decolorization taking crystal violet, methyl orange, methylene blue, brilliant green and methyl red dyes supplemented in LB medium. The bacterium showed maximum brilliant green degradation ability was analyzed using UV-Vis and FTIR analyses to characterize the degraded product. The highest brilliant green degradation activity of the A. insolitus in the present study could be exploited for bioremediation of brilliant green contaminated industrial effluents in a ecofriendly and cost effective way.

Degradation of Dimethyl Phthalate and Diethyl Phthalate by Bacteria Isolated from Jazan, Saudi Arabia

P hthalate esters (PAEs) are commonly utilized in commercial, industrial, and medical applications. Various concentrations of PAEs have been detected in seawater samples and treated wastewater obtained from wastewater treatment plants in Saudi Arabia. Since these compounds pose adverse effects to human health, it is vital to develop efficient strategies to eliminate phthalate contamination from environments. In the present study, an enrichment technique was used to isolate phthalate-degrading bacteria from seawater and from activated sludge collected at Jazan Wastewater Treatment Plant, Saudi Arabia. Bacteria with the capability of degrading dimethyl phthalate (DMP) or diethyl phthalate (DEP) were isolated using minimum salt medium supplemented with these compounds as the sole carbon and energy source. High-performance liquid chromatography (HPLC) was utilized to evaluate the residual concentration of DMP and DEP. Using the 16S rRNA gene sequencing technique, the isolates with maximum DMP biodegradation activity were identified as Achromobacter sp. M1 and Pseudomonas sp. M2, while the isolates with maximum DEP biodegradation activity were identified as Pseudomonas sp. E2 and Pseudomonas sp. E3. The optimum bacterial growth was achieved at 30°C, pH 7.0, and 2% NaCl, except for Pseudomonas sp. E3, which demonstrated its maximum growth in the absence of NaCl. The highest biodegradation rate for all the bacterial strains (> 99.0%) was achieved at 30°C, pH 7.0, and up to 2% NaCl within 4 days. Concurrently, Pseudomonas sp. M2 and Pseudomonas sp. E2 exhibited remarkable degradation rates (97.5% and 56.7%, respectively) at 4% NaCl whereas Pseudomonas sp. E3 showed its highest DEP degradation (82.4%) after 4 days in the absence of NaCl. This study offers potential candidates, including Achromobacter sp. M1, Pseudomonas sp. M2, Pseudomonas sp. E2, and Pseudomonas sp. E3, for the proficient biodegradation of DMP and DEP.

Exploring the potential of bacterial consortium for the treatment of paper mill effluent treatment through various treatment strategies and evaluation of their toxicity

Paper mill effluent containing kraft lignin (KL) and other toxic compounds poses serious environmental health concerns due to its potential for bioaccumulation. A prospective bacterial consortium is still needed for the remediation of paper mill effluent. Therefore, the current work aims to explore the potential of consortium, i.e. Bacillus cereus, B. paramycoides, and B. aryabhattai via different treatment strategies: batch, continuous, multipulse, and dissolved oxygen (DO) stat fed-batch for maximum detoxification of effluent under optimised conditions. A minimal salt medium containing 1.0 % glucose, 0.5 % ammonium nitrate, and pH 8.0 was the optimum condition for the consortium to degrade 1000 mg/L of kraft lignin in the effluent. Laboratory adaptation evolution (LAE) studies showed that the maximum number of bacterial generations was observed within 178 h at 5th cycle for 3000 mg/L kraft lignin. The maximum removal of KL, color, chemical oxygen demand (COD), biological oxygen demand (BOD), and total phenol by the dissolved oxygen stat fed-batch treatment strategy was 94 %, 86 %, 91 %, 90 %, and 97 %, respectively. Phytotoxicity testing of the consortium-treated effluent on Vigna radiata L., and Trigonella foenum-graecum L. revealed a reduction in phytotoxicity by ∼66 % and ∼68 %, respectively. The genotoxicity study on Allium cepa L. showed that the percent of aberrant cells with different chromosomal aberrations was decreased in consortium-treated effluent as compared to untreated effluent. This work provides a new insight and strategy for the paper mill effluent treatment at an industrial scale. Statement of environmental implicationThe paper mill effluent contains various hazardous compounds; chlorinated phenols, dioxins, kraft lignin, and endocrine disrupting compounds, when discharge from industries without proper treatment. This effluent causes mutagenic, clastogenic, carcinogenic, and endocrine-disrupting mechanisms in flora and fauna. This study provides a comparative performance evaluation of different treatment strategies: batch, continuous fed-batch, multipulse fed-batch, and dissolved oxygen stat fed-batch, for paper mill effluent treatment using a bacterial consortium for maximum removal of kraft lignin, color, chemical oxygen demand, total phenol concentration, and quantified ligninolytic enzyme production. Treated effluent showed a lesser phytotoxic and genotoxic effect. Therefore, the results of this study are suitable for environmental restoration. Significance of studyContrastingly, throughout this study, found that bacterial consortium have superior detoxifying qualities of paper mill effluent compared to pure cultures, via different treatment strategies: batch, continuous, multipulse, and dissolved oxygen stat fed-batch strategies under optimised conditions at lab scale. According to these results, such dissolved oxygen stat fed-batch strategy mediated treated effluent that promotes seed germination and showed a higher mitotic index of root cells of the plant in contrast to untreated effluent. Therefore, these treatment strategies are adequate, effective, and sustainable to reduce the significant pollution load in effluent.

Biodegradation of phenolic derivatives by Rhodosporidium toruloides: Effect on growth, cell morphology, lipid and biodiesel production

Phenol derivatives are considered one of the most hazardous pollutants, posing a significant risk to the ecosystem. The present study investigates the ability of the Rhodosporidium toruloides 9564T to degrade the selected phenol derivatives, i.e., catechol, 4-chlorophenol (4-CP), and 4-nitrophenol (4-NP), and simultaneously produce lipids. The experiments were performed using minimal salt media with varying ranges of catechol (0.25 g/L–1.5 g/L), 4-CP (0.25–1.5 g/L), and 4-NP (0.1–1 g/L) with a 10 % inoculum size. Results showed that R. toruloides 9564T completely degraded 1 g/L catechol, 0.5 g/L 4-CP, and 0.1 g/L 4-NP. In comparison with the two phenol derivatives, the maximum biomass (2.096 ± 0.093 g/L), total lipid (0.774 ± 0.031 g/L), and lipid content (36.92 ± 0.147 %.) produced during catechol degradation. The GC analysis revealed the percentages of saturated fatty acids in lipids were 66.21, 86.43, and 81.39 % for catechol, 4-CP, and 4-NP. Catechol, 4-CP, and 4-NP biodiesel qualities (cetane number, cloud point, pour point, viscosity, etc.) matched ASTM-D6751 and EN 14214. To assess the potential environmental impact, the degraded samples by yeast were analyzed for phytotoxicity, which exhibited reduced toxicity. Consequently, R. toruloides proves to be a promising agent for valorizing wastewater treatment for biodiesel production.

Optimization of Growth Conditions for Chlorpyrifos-Degrading Bacteria in Farm Soils in Nakuru County, Kenya.

Chlorpyrifos (CP) is a chlorinated organophosphate pesticide. In Kenya, it is commonly used as an acaricide, particularly in dairy farming, leading to soil and water contamination. The study is aimed at isolating bacteria with CP-degrading potential and optimizing their growth conditions, including temperature, pH, and CP concentration. The enrichment culture technique was used, with minimal salt medium (MSM) supplemented with commercial grade CP. A multilevel factorial design was used to investigate the interactions of temperature, pH, and CP concentration. According to the findings, seven bacterial strains with potential to degrade CP were characterized and identified as Alcaligenes faecalis, Bacillus weihenstephanensis, Bacillus toyonensis, Alcaligenes sp. strain SCAU23, Pseudomonas sp. strain PB845W, Brevundimonas diminuta, and uncultured bacterium clone 99. Growth and biodegradation of bacteria differed significantly among the isolates across pH value, temperature, and concentrations (P ≤ 0.05). The optimum conditions for growth were pH 7, temperature of 25°C, and 25mg/l chlorpyrifos concentration, while optimum degradation conditions were pH 5, temp 25°C, and CP conc. 25mg/l. The Pearson correlation between optimum growth and degradation showed a weak positive relationship (R = 0.1144) for pH and strong positive relationship for temperature and concentration of chlorpyrifos. Other than pH, the study shows that there could be other cofactors facilitating the chlorpyrifos degradation process. The findings show that an efficient consortium, at 25°C and pH 5, can include Bacillus toyonensis 20SBZ2B and Alcaligenes sp. SCAU23 as they showed high optical density (OD) values under these conditions. These results indicate the potential for these bacteria to be employed in chlorpyrifos-contaminated ecosystem detoxification efforts upon manipulation of natural growth conditions. The findings of this study offer a potential foundation for future research into the reconstitution of a consortium. Based on the optimum conditions identified, the isolated bacterial strains could be further developed into a consortium to effectively degrade CP in both laboratory and field conditions. Dairy farmers can utilize the isolated strains and the consortia to decontaminate farm soils.

Methods used to determine the structure of the oxygenase component of naphthalene 1,2 dioxygenase.

Rieske non-heme iron oxygenases are ubiquitously expressed in prokaryotes. These enzymes catalyze a wide variety of reactions, including cis-dihydroxylation, mono-hydroxylation, sulfoxidation, and demethylation. They contain a Rieske-type [2Fe-2S] cluster and an active site with a mono-nuclear iron bound to a 2-His carboxylate triad. Naphthalene 1,2 dioxygenase, a representative of this family, catalyzes the conversion of naphthalene to (+)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene. This transformation requires naphthalene, two electrons, and an oxygen molecule. The first structure of the terminal oxygenase component of a Rieske non-heme iron oxygenase to be determined was naphthalene 1,2 dioxygenase (NDO-O). In this article, we describe in detail the methods used to recombinantly express and purify NDO-O in rich and minimal salts media, the crystallization of NDO-O for structure determination by X-ray crystallography, the challenges faced, and the methods used for the preparation of enzyme ligand complexes. The methods used here resulted in the determination of several NDO-O complexes with aromatic substrates, nitric oxide, oxygen molecule, and products, leading to an initial understanding of the mechanism of enzyme catalysis and the molecular determinants of the regio- and stereo-specificity of this class of enzymes.

ISOLATION AND CHARACTERIZATION OF PHENOL METABOLIZING BACILLUS CEREUS STRAIN SBBP4

US Environment Protection Agency has categorized phenol and its derivatives as persistent organic pollutants (POPs) due to the associated deleterious effects. Conventional mitigation approaches due to the complex procedures, high cost and involvement of lots of man power have failed in clearing this pollutant from ecosystem. Bioremediation based on bacteria can replace these conventional approaches due to simpler technology and low cost. In present study, we have tried to isolate and characterize phenol metabolizing bacteria from tannery industry soil. Isolation was carried out using minimal salt media (MSM) and serial dilution method. Followed this, bacterium was analyzed via growth curve analysis, ribotyping, biochemical testing, antibiotic sensitivity profiling, phenol removal assay and FTIR analysis. Bacterium was identified to be Bacillus cereus. It was fast growing capable of removing 98.7% phenol. It exhibited resistance against amoxicillin, augmentin, cefadroxil, and cephalexin. Comparison of FTIR spectra of control vs bacterial sample also showed slight variation in peaks indicating the change in bonds of phenol in the presence of present study isolate. Bacterium Bacillus cereus strain SBBP4 can be investigated for further optimization and employed for efficient phenol removal.

Development of Cupriavidus necator H16 as a host for heterologous production of formate dehydrogenase I of Methylorubrum extorquens: Possibilities and limitations

The discovery of formate dehydrogenase (Me-FDH1) from Methylorubrum extorquens has provided an avenue for sustainable CO2 fixation and utilization. However, the mass production of Me-FDH1 is challenging due to the presence of its unique tungsto-bis-metalopterin guanine dinucleotide (W-bis-MGD) cofactor, limiting its practical applications. In this study, C. necator H16 is proposed as a host for the large-scale production of Me-FDH1, utilizing fructose as a carbon source and its inherent machinery for cofactor synthesis. In a minimal salt medium, C. necator H16 could produce active Me-FDH1, which exhibited a specific activity of 80 to 100 U/mg for CO2 conversion to formate. In fed batch bioreactor experiments, approximately 50 g CDW/L (cell dry weight/L) and 10,000 U/L Me-FDH1 were achieved within 50 h. This study highlights C. necator H16 as the recombinant host for Me-FDH1, paving the way for the future development of efficient mass-production methods for this crucial enzyme.

Treatment of 2-naphthalene sulfonate by free and immobilized cells of indigenous isolate Comamonas sp. C2 and toxicity evaluation of biotransformed sample

An indigenous bacterial strain Comamonas sp. C2, capable of utilizing 2-naphthalene sulfonate (2-NS) as a sole source of carbon, was isolated after enrichment of microbial diversity present in sample collected from sewage treatment plant (STP) receiving untreated or partially treated effluent from textile industries. The isolate was able to degrade 100 mg/L of 2-NS, when grown in sulfur free minimal salt medium (SFMSM), after an incubation of 8 h. The release of sulfite/sulfate ions during biotransformation, assay of protocatechuate 4, 5-dioxygenase activity and formation of metabolic intermediates like salicylaldehyde, protocatechuate and 2-hydroxy-4-carboxy-muconatesemialdehyde in the biologically treated sample indicated to the meta-cleavage of aromatic ring of 2-NS. An immobilized-cell plug flow bioreactor (PFR) was developed and evaluated for its efficiency to treat simulated feed supplemented with 100 mg/L of 2-NS. The cells of C2 were immobilized on pieces of polyurethane foam (PUF) and refractory brick pieces (RBP). The PFR, when operated at an HRT of 36 h, achieved complete degradation of 100 mg/L of 2-NS corresponding to 89% lowering of COD. The reduction in overall toxicity of 2-NS after biological treatment was evaluated using plant (Triticum aestivum and Vigna radiata) and animal (freshwater fish Channa punctatus) models, exposed to both untreated and PFR treated samples. To the best of our knowledge, there are no similar reports on exploitation of the metabolic potential of Comamonas sp. in 2-NS degradation and validation of the biological transformation by toxicity analysis.

Impact of biosurfactant produced by Bacillus spp. on biodegradation efficiency of crude oil and anthracene

Biosurfactants are surface active molecules generated by various microorganisms, including bacteria, actinobacteria, algae, and fungi. In this study, bacterial strains are isolated from soil contaminated with used motor oil and examined for potential biosurfactant production. A minimum salt medium (MSM), with crude oil as the only carbon source, is used to isolate potential biosurfactant-producing bacterial strains. About 23 strains are isolated, and all are subjected to the primary screening methods for biosurfactant production. Based on the emulsification index, oil displacement, and drop collapse screening methods, two isolates with potential biosurfactant-producing ability are selected for further studies. The synthesis of biosurfactants, crude oil and anthracene biodegradation is carried out with strains DTS1 and DTS2. Both strains show significant outcomes in crude oil degradation. In addition, both strains can utilize anthracene as the sole carbon source. During the degradation course, changes in the growth conditions are continuously monitored by measuring turbidity and pH. In this degradation study, the biosurfactant production aptitude of the isolated strains plays an essential role in increasing the bioavailability of hydrophobic hydrocarbons. These strains are identified down to the molecular level by employing 16S rRNA gene sequencing, and the acquired sequences are submitted to get the accession numbers. These prospective strains can be utilized to remediate hydrocarbon-contaminated environments.

Isolation and Characterization of Phenol degrading Bacteria from Wastewater

Out of 30 bacterial isolates from wastewater were checked for growth on a minimal salt medium amended with different concentrations of phenol by flask culture technique. The eight most tolerant bacterial strains to the higher concentrations of phenol, designated as W2, W5, W9, W12, W14, W15, W19 and W29, were investigated for their ability to grow and degrade phenol. Among the eight higher phenol degrading isolates, W15 can tolerate up to 1000 ppm of phenol concentrations and grow and degrade 94% of phenol within 72 hrs. The optimum temperature and pH condition were 37C◦ and 7, respectively. The yeast extract is the best organic nitrogen source, while ammonium chloride is the best inorganic nitrogen source for the growth and degradation of phenol.

Assessment and Biodegradation of Polycyclic Aromatic Hydrocarbons in Soil and Water Around Petroleum Products Depot Suleja, Nigeria.

Petroleum contamination constitutes a frequent incidence in various petroleum depots in Nigeria. In this study, the polycyclic aromatic hydrocarbons (PAHs) present in soil and water in communities around Petroleum Products Marketing Company (PPMC) Suleja, Nigeria, were evaluated and degraded using indigenous microorganisms. The samples sites were divided into 7 plots from where samples of water and soil were obtained: one within the PPMC depot, five from communities surrounding the depot, and the control 93,000km from the depot. The microbial counts were determined using spread plate inoculation technique on minimal salt media. The microbial isolates were characterized and identified based on their cultural, biochemical, and molecular characteristics. The potential of the microbial isolates to utilize 0.05 mL of diesel, kerosene, engine oil, and crude oil was determined in a Bushnell Haas Broth, and the biodegradation was determined by total viable cell counts and spectrophotometry. The ability of the isolates to mineralize PAHs was also evaluated in a minimum salt media. The bacterial isolates were species of Streptococcus, Pseudomonas, Staphylococcus, Proteus, Escherichia, and Bacillus, while species of Penicillium, Aspergillus, Mucor, and Rhizopus were isolated among the fungi. Aspergillus niger strain ATCC 1015 and Bacillus thuringiensis strain M43 showed high capacity to utilize the 16 priority PAHs. The pahE1 gene was used by Bacillus thuringiensis, Pseudomonas aeruginosa and A. niger, while Penicillium notatum used pahE2 gene for the degradation of the PAH. The current study identified microbial isolates that can utilize priority PAHs, making them beneficial for oil spill bioremediation in tropical environments.

General nitrogen regulation protein NtrC regulates the expression of nitrile hydratase and the synthesis of extracellular polysaccharide in Ensifer adhaerens CGMCC 6315

Ensifer adhaerens CGMCC 6315 contains two nitrile hydratases, CnhA and PnhA, which both convert the neonicotinoid insecticide acetamiprid to its amide metabolite. Here, we report that upregulation of PnhA and CnhA expression is related to nitrogen metabolism. Proteomic analysis showed that general nitrogen regulation protein NtrC was upregulated under nutrient deprivation. We thus constructed a ΔntrC mutant strain of E. adhaerens CGMCC 6315. In the ΔntrC strain, when cells were cultured in minimal salts medium supplemented with ammonium chloride, acetamiprid degradation and the expression of cnhA and pnhA were enhanced relative to those in wild-type E. adhaerens CGMCC 6315. In addition, NtrC negatively regulates synthesis of extracellular polysaccharides in this bacterium. The germination rate of soybean seeds was improved by inoculation with the ΔntrC strain of E. adhaerens CGMCC 6315 compared with the wild-type. This study is the first to report regulation of the expression of nitrile hydratase by NtrC, which is important for the practical remediation of pesticide pollution.

Biotransformation of Lignocellulosic Biomass Hydrolysate into Polyhydroxybutyrate Biopolymer via Ralstonia Eutropha

Currently, a rampant cultural shift is occurring in the modern world to progressively substitute fossil-derived plastics and shift to novel biomaterials that are benign to the environment owing to increased awareness of environmental sustainability along with the implementation of strict regulations worldwide. Polyhydroxyalkanoates (PHAs) are promising intracellular biodegradable polymers that have attracted considerable focus owing to their biocompatibility, biodegradability, non-toxicity and environment-friendly nature to function in diverse applications notably in the pharmaceutical, medical, textile, materials, fuel, agricultural industries. Nonetheless, despite its huge market potential, the commercial growth of PHA is achieved on a small extent only, since the cost-effectiveness of this product is highly debatable owing to the high production cost of processing the carbon substrate. The goal behind this research study is to explore the possibility of exploiting low-cost carbon substrates from low-value lignocellulosic materials that would have otherwise been discarded as waste and add stress to the landfill to manufacture biopolymer compounds that are used in everyday lives as well as to enhance the functionality and yields of glucose from PHA substrates that can undergo industrial upscaling. One of the major challenges of transforming lignocellulosic biomass into fermentable sugars is the recalcitrant nature of the fibre which renders it very resistant to the release of sugars for fermentation. Since lignocellulosic biomass has a specific attribute such as an extremely coordinated matrix which renders it very resistant to the release of sugars for fermentation owing to biological degradation, a pre-treatment phase is necessary prior to the hydrolysis stage for the transformation of the fermentable sugars. This study focuses on the biosynthesis of biopolymers from lignocellulosic biomass through sustainable approaches such as enzyme and microbial activities in order to examine its viability as a replacement for traditional polymers. Cupriavidus Necator H16 (Ralstonia Eutropha) having 8×108 CFU/ml viable colonies were cultured at 30 oC and was inoculated in submerged fermentation of M9 minimal salt medium using 1% reducing sugar from Furcraea Foetida as carbon source. Batch fermentation of PHB in submerged cultivation conducted for a residence time from 0 to 48h resulted in a dry cell weight from 0.32±0.05% to 1.62±0.05%. The nitrogen limiting phase was achieved after 48h and 17.05±0.35% of PHB was extracted from 3ml of the fermentation broth. The PHB yield was dramatically lower than reported optimal yields of 37.55 to 97.80% from works of literature. Nonetheless, Fourier-transform infrared spectroscopy (FTIR) spectroscopy revealed characteristics bands for carbonyl, methine and ester groups along with intermolecular hydrogen bonds in the biopolymer. Sudan Black B and FTIR spectrum demonstrate that PHB biosynthesis successfully bioaccumulates inside the cells of Ralstonia Eutropha using cellulose from Lignocellulosic biomass (LCB) as carbon source. Hence, the process needs to be optimized in terms of variables such as inoculum size, inoculum concentration, incubation time and salt medium conditions in order to maximise the production of PHB from Furcraea Foetida in Ralstonia Eutropha cultivation.