Mineral Salts Medium Research Articles

Efficacy of soil-borne Burkholderia Cepacia-Like MB-01 strain for shobicron and vertimec degradation

Pesticides are necessary in agriculture, yet their highly toxic ingredients harm the ecosystem. Due of their toxicity, uncontrolled releases of large quantities of pesticides pollute the environment and provide a larger health risk to plants, animals, and humans. Bacteria are capable of degrading such pollutants and saving our ecosystem. In this work, a bacterial strain was isolated from Shobicron and Vertimec-treated lady's finger soil using enrichment culture. The strain was identified as Burkholderia Cepacia-Like MB-01 based on morphological, physiological, and biochemical traits, as well as phylogenetic analysis of the 16SrRNA sequence. The bacterium grew best at 35 °C with a pH of 7. Furthermore, it was susceptible (S) to Cefepime and Penicillin but intermediate (I) resistant to Carbapenem and Tetracycline and resistant (R) to Ciprofloxacin, Kanamycin, and Gentamycin in an antibiotic sensitivity test. The rate of shobicron and vertimec degradation was measured over a five-day period using Mineral Salt (MS) medium. In its optimum growth condition, shobicron and vertimec degradation rates were determined to be around 76 % and 80 %, respectively. The isolated bacterial strain was found to be capable of detoxifying shobicron and vertimec in the experiment. As a result, the bacterial strain could be exploited as a possible shobicron and vertimec degrader for pesticide bioremediation.

Characterization of Cypermethrin-degradation by a Novel Molybdenum-reducing Morganella sp. Isolated from Active Agricultural Land in Northwestern Nigeria

The increasing use of cypermethrin in agricultural fields, household and industrial applications for effective pest control had increased the global burden of the pollutant over the years. Consequently, there is an urgent need to devise techniques to eliminate this pollutant from the environment. A bacterium capable of degrading cypermethrin has been successfully screened and characterized. The bacterium was grown in a mineral salt medium (MSM) supplemented with cypermethrin as its sole carbon and energy source at an optimum pH 7.5, temperature 40 ºC, a carbon source concentration of 4 g/L, optimum incubation time of 24 h and an inoculum size of 400 µL. The potential of Morganella sp. to degrade cypermethrin makes it an important instrument for the degradation of cypermethrin. This knowledge may be useful for the optimization of environmental conditions for cypermethrin bioremediation and important for detoxification of cypermethrin polluted sites.

Environmental Assessment of Petrophilic Bacteria Associated with ‎Bioremediation and Biodegradation of Engine Oil Contaminated Soil in ‎Maiduguri

Soil contamination by petroleum hydrocarbons is a major problem resulting from activities related to petroleum industry, automobile service stations and accidental release of oil in the soil. Bioremediation/biodegradation can be considered as an effective aid to clean up oil spills, aside from conventional methods that are uneconomical and produce residues that harm the surrounding biota. There are an estimated over 250 mechanic shops with more than 5000 technicians in Maiduguri. Mechanics working therein frequently spill oil which is a potent source of immunotoxicants and carcinogenic to humans and animals. The aim of this study was to screen for petrophilic bacterial isolates from engine oil contaminated soil, that can utilize crude oil as sole source of carbon for growth in Maiduguri Metropolis. Ten isolates from engine oil contaminated soils in Bola and Tashan Kano areas of Borno State were obtained. The bacteria were individually cultured in Bushnell Haas Mineral Salt Medium devoid of carbon source except for crude oil for 21 days at 370C. Bacterial growth from visible increased turbidity was enumerated by CFU/g on nutrient agar. Pseudomonas sp. isolate exhibited relatively higher ability to grow on crude oil with TNTC followed by Bacillus sp., 6.7×104, Arthrobacter sp.,6.5×104, Flavobacterium sp.,6.2×104, Pseudomonas sp., 6×104, Nocardia sp.,5.9×104, Acinetobacter sp., 5×104, Bacillus sp., 5×104. Proteus sp., 4.7×104 and Flavobacterium sp. 4×104. It is therefore concluded that all the bacterial genera present in this study are effective hydrocarbon oil degraders.

Degradation of polystyrene by tropical bacterial and fungal isolates

Plastic waste is one of the major contributing factors to the growth of municipal solid wastes globally. It is a threat to public health and negatively impact the aquatic and terrestrial animals due to its persistence in the environment. Bacterial and fungal isolates were tested for their ability to degrade polystyrene. The cultures were grown on mineral salts medium supplemented with polystyrene as the sole carbon source in 250 mL conical flasks. The polystyrene reduced from 1 g (week 0) to 0.7g (week 7). Statistical analysis of variance (one-way ANOVA) shows a significant difference between the reduction in weight of polystyrene in the experimental flask compared to the control (P<0.05). Gas chromatography mass spectrometry analysis of biodegradation products shows that some toxic polystyrene constituents such as O-xylene, cis-9-hexadecenal and 3-phenol pentadecyl were removed.

Isolation of Halomicroarcula pellucida strain GUMF5, an archaeon from the Dead Sea-Israel possessing cellulase.

A strain designated GUMF5 was isolatedin Goa-India from sedimentsof Dead Sea-Israel and identified as haloarchaeon Halomicroarcula pellucida based on 16S rRNA gene analysis similarity value of 99.84%. Strain GUMF5 grew on mineral salts medium with 20% NaCl and 0.5% carboxymethyl cellulose-sodium (CMC-Na) as a sole source of carbon and produced haloextremozyme cellulase. The enzyme was concentrated using Sephadex G20, precipitated with ethanol, dialyzed and retentate purified using Sephadex G200, the size exclusion chromatography. A yield of 78.53% cellulase with an activity of 131.13 U/mg and 1.24-fold purity was obtained. The purified cellulase had optimum activity at 20% NaCl, at 40 ºC, 0.5% CMC-Na, pH 7 and 150rpm. SDS-PAGE combined with zymographic analysis revealed the molecular weight of cellulase as 240kDa, 40kDa and 17.4kDa. The activity of the enzyme was stimulated by metallic cations in the order of Ca+2 > Mn+2 > Mg+2 > SO4 2- > NH4 + and was inhibited by Ag+ > Fe+2 > Cu+2. Methanol and ethanol enhanced the cellulase activity by 6% and 26%, respectively. The haloextremozyme cellulase degraded Whatman No. 1 filter paper indicated in scanning electron micrographs, exposure of open pores and fibers without any intra connectivity corresponding to paperase activity and implicating the possible use of enzyme to bio-convert cellulosic waste. Conclusively, Halomicroarcula pellucida GUMF5 (Accession number: MH244431), globally, is the only Halomicroarcula pellucida isolated from the sediments of Dead Sea producinghaloextremozyme cellulase, and hence is an important biotechnological resource.

Screening of cultivation media for LDPE biodegradation by Penicillium verrucosum CNM-FP-02

The paper’s aim was to select the optimal mineral medium for LDPE biodegradation by the strain Penicillium verrucosum CNM-FP-02. It was selected 5 mineral salt media (MSM), which differed in salt content and N/P ratio. After 40 days of submerged cultivation, the following parameters were determined: catalase activity and pH of cultural media, biomass accumulation, rate of LDPE degradation, optical microscopy and the tensile testing of polyethylene. It was observed that catalase activity on all media, except MSM 4, was higher in the presence of LDPE. The addition of polyethylene to the growth media stimulated the fungal biomass accumulation by 19.3-93.1% (4 media out of 5 tested). The percentage of degradation of LDPE films was different, depending on the culture medium, from 0.41% to 0.92%. The most active LDPE films were degraded on medium MSM 2. Visualization of plastic strips under an optical microscope revealed the immobilization of the microorganism and the damage on the polyethylene surface. The tensile test showed increased elasticity of the plastic in the variants treated with fungal strain. In conclusion, in order to stimulate the biodegradation of LDPE by the strain P. verrucosum CNM-FP-02, the medium MSM 2 (N/P ratio 1:1) was selected.

Isolation and Identification of Anthracene Utilizing Proteus vulgaris from Oil Spill Contaminated Soil at NNPC Depot Kano State Nigeria

Microbial biodegradation of polycyclic aromatic hydrocarbons (PAHs) like Anthracene, represent an efficient, time, and cost-effective way for bioremediation of the polluted environment. This study was aimed at isolating, identifying and characterizing bacteria with potential to degrade and utilize anthracene as a sole carbon source. A bacteria was isolated from oil spilled contaminated site located in Kano, using an enrichment method on mineral salt media (MSM) following serial dilution (10-1-10-6). Characterization was done by studying the effects of temperature and pH on mineral salt media (MSM) containing anthracene. The isolate was then identified morphologically, biochemically and molecularly based on 16S rRNA partial gene sequence analysis. The morphological and microscopic examination of the isolate from this research shows that the isolate was creamy in color, motile, gram negative, short rod and non-spore forming respectively. The biochemical test of the isolate was found to be positive for these parameters (methyl red, catalase, motility, indole and urease) and negative for (citrate and oxidase). The 16S rRNA sequence and Phylogenetic analysis using neighbor joining tree and 1000 boos trap revealed that, the isolate was closely related (on the same clade) to Proteus vulgaris with accession number MW766369. Characterization was done by studying the effects of temperature and pH. The isolated bacterium was optimal at a temperature of 35ºC and pH 7.5. This isolate is a promising strain that could be used in bioremediation of polycylic aromatic hydrocarbons polluted environment.

Characterization of bacterial community in oil-contaminated soil and its biodegradation efficiency of high molecular weight (>C40) hydrocarbon

In this study, two biosurfactant producing Pseudomonas aeruginosa sp. were isolated from motor oil contaminated soil for crude oil, alkane and PAH degradation studies. Metagenomics analysis identified as proteobacteria phyla was the dominant. Isolated two bacterial species were well grown in mineral salt medium with 1% of crude oil, alkanes (dotriacontane and tetratetracontane) and PAH (pyrene, benzopyrene and anthracene) as sole carbon sources. Total biodegradation efficiency (BE) of strains PP3 and PP4 in Crude oil degradation evaluated by the analysis of gas chromatography and mass spectrometry was 50% and 86% respectively. BE of PP3, PP4 and mixed consortium in alkane biodegradation were 46%, 47% and 36%, respectively. BE of PP3, PP4 and mixed consortium in PAH biodegradation were 22%, 48% and 35%, respectively. Based on the results revealed that strain pp4 was more efficient bacteria to degrade the crude oil, alkane and PAH than pp3. This was due to the higher production of biosurfactant by PP4 than PP3 and also confirmed in the test of emulsification index (E24). FTIR results showed that the produced biosurfactant could partially solubilize the crude oil hydrocarbons, alkanes and PAH and confirmed as glycolipid (rhamnolipid) in nature. Thus, the obtained results from the GCMS showed that all hydrocarbons were utilized by bacteria as carbon source for biosurfactant production and utilize the high molecular weight hydrocarbons. Based on the present study we can suggest that identified potential biosurfactant producing bacteria are used for biodegradation of high molecular weight hydrocarbon (>C40).

EVALUATION OF AZO DYE ORANGE G DECOLORIZATION AND DEGRADATION BY BACTERIA ISOLATED FROM TEXTILE EFFLUENT

The bacteria were isolated and identified from textile effluent, and their ability to decolorize the hazardous azo dye Orange G was evaluated. After incubating the isolates for 24 hours in mineral salt medium supplemented with 100 ppm Direct Orange G, their decolorizing activity was measured spectrophotometrically. Lysinibacillus sp. AUBTP7 (AK1), Bacillus muralis strain1Y118 (AK2), and Bacillus thuringiensis strain N3 (AK3) were identified as the bacterial strains. Bacillus thuringiensis strain N3 (AK3) was the most efficient bacteria at decolorizing Orange G (100ppm), removing 93% of the color in 24 hours at 36ºC temperature. Study of HPLC chromatogram of Orange G and degradation products suggests the formation of new compounds. As a result of this research, it has been revealed that some bacteria live in textile effluents and use dyes as a source of energy and nourishment, implying their usefulness in the treatment of industrial effluents.

Surface Properties and Adherence of Bradyrhizobium diazoefficiens to Glycine max Roots Are Altered When Grown in Soil Extracted Nutrients

Soybean roots are colonized and nodulated by multiple strains of compatible nitrogen-fixing rhizobia primarily belonging to the Genus Bradyrhizobium. Motility towards the root and attachment to root hairs are key determinants of competitive colonization and subsequent nodulation. Bacterial surface properties and motility are known to vary with chemical composition of the culture medium, and root adhesion and nodulation occur in a soil environment rather than laboratory medium. We asked whether the nodulation-promoting factors motility, surface hydrophobicity and surface adhesion of Bradyrhizobium are affected by growth in a soil nutrient environment. B. diazoefficiens USDA 110, 126, 3384, and B. elkanii USDA 26 were grown in mineral salt medium with peptone, yeast extract and arabinose (PSY), and in a soil extracted soluble organic matter (SESOM) medium. Surface hydrophobicity was determined by partitioning into hydrocarbon, motility by transition through soft agar, and surface-exposed saccharides by lectin profiling, followed by biofilm formation and soybean root adhesion capacity of populations. SESOM-grown populations were generally less motile and more hydrophobic. They bound fewer lectins than PSY-grown populations, indicating a simpler surface saccharide profile. SESOM populations of USDA 110 did not form detectable biofilm, but showed increased binding to soy roots. Our results indicate that growth in a soil environment impacts surface properties, motility, and subsequent soy root adhesion propensity. Hence, evaluation of Bradyrhizobium for nodulation efficiency should be performed using soil from the specific field where the soybeans are to be planted, rather than laboratory culture media.

Removal of lindane in liquid culture using soil bacteria and toxicity assessment in human skin fibroblast and HCT116 cell lines

ABSTRACT The development of effective measures for the remediation of lindane contaminated sites is the need of the hour. In this study, a potent lindane degrading bacteria, identified as Rhodococcus rhodochrous NITDBS9 was isolated from an agricultural field of Odisha that could utilize up to 87% of 100 mg L−1 lindane when grown under liquid culture conditions in mineral salt media in 10 days. The bacteria could produce biofilm in lindane-containing media. Rhodococcus rhodochrous NITDBS9 was further characterized for its plant growth-promoting properties and it was found that the bacteria showed abilities for phytohormone, ammonia and biosurfactant production, etc. This could be beneficial for the bioremediation and improvement of crop production in contaminated sites. Ecotoxicity studies carried out for lindane, and its degradation products in mung bean and mustard seeds showed a reduction in toxicity of lindane after treatment with NITDBS9. NITDBS9 was used with a previously isolated potent lindane degrading strain Paracoccus sp. NITDBR1 in a dual mixed culture for the enhanced removal of lindane in the liquid system i.e. up to 93% in 10 days. Cytotoxicity studies were conducted with lindane before and after treatment with the single and dual mixed cultures on human skin fibroblast and HCT116 cell lines. They revealed a significant reduction in toxicity of lindane after it was bioremediated with the single and dual mixed cultures. Therefore, our proposed strategy could be efficiently used for the detoxification of the lindane-contaminated system, and further work should be done to study the use of these cultures in the contaminated soil system.

Growth Optimization of Glyphosate-based Herbicides Utilizing Bacteria isolated from Lotic Water of Ogini Stream, Nigeria

Glyphosate-based herbicides are often used for the control of weeds grown on agricultural fields or farms. Different health problems have been reported to be associated with the use of glyphosate-based herbicides mainly due to their toxicity level. Thus, finding glyphosate utilizing microorganisms to remediate the glyphosate-based herbicides in the environment is crucial. The culture conditions for maximum utilization of glyphosate by bacterial isolates, Stenotrophomonas maltophilia, Bacillus cereus and Enterobacter aerogenes previously isolated from Ugini stream close to corn fields treated with glyphosate-based herbicide at Ofagbe, Delta State, Nigeria were optimized using mineral salt medium containing glyphosate as carbon source. The varied culture parameters assessed were temperature (30, 37 and 40 oC), pH (5, 6, 7, 8 and 9), initial glyphosate concentration (1, 3, 5, 7 and 9 g/L) and incubation time (2-14 days). Optical density (OD) at 560 nm of the culture was used to estimate cell growth or cell load of the glyphosate utilizing bacteria strains at every 2 days for 14 days. The following optimal conditions were determined: initial pH 9.0, incubation temperature 30 °C, initial concentration of glyphosate (1g/L) and incubation time of 12 days. Of the isolates on the medium containing the herbicide as sole carbon and energy source, Bacillus cereus showed the highest growth level (OD average, 0.127, pH average, 6.26. This was followed by Stenotrophomonas maltophilia (OD average = 0.114, pH average = 6.44) and Enterobacter aerogenes (OD average = 0.100, pH average, 6.56). At the increased of glyphosate in the medium there was decreased in growth of the bacteria. Bacillus cereus, Stenotrophomonas maltophilia and Enterobacter aerogenes indicated a high capacity to be able to degrade glyphosate. It is therefore concluded that the bacteria employed in this research can be recommended for bioremediation of environments contaminated with this chemical and further research should conducted to ascertain the catabolic genes present in these individual glyphosate degrading bacteria.

Characterization and genomic analysis of an efficient dibutyl phthalate degrading bacterium Microbacterium sp. USTB-Y.

A promising bacterial strain for biodegrading dibutyl phthalate (DBP) was successfully isolated from activated sludge and characterized as a potential novel Microbacterium sp. USTB-Y based on 16S rRNA sequence analysis and whole genome average nucleotide identity (ANI). Initial DBP of 50mg/L could be completely biodegraded by USTB-Y both in mineral salt medium and in DBP artificially contaminated soil within 12h at the optimal culture conditions of pH 7.5 and 30℃, which indicates that USTB-Y has a strong ability in DBP biodegradation. Phthalic acid (PA) was identified as the end-product of DBP biodegraded by USTB-Y using GC/MS. The draft genome of USTB-Y was sequenced by Illumina NovaSeq and 29 and 188 genes encoding for putative esterase/carboxylesterase and hydrolase/alpha/beta hydrolase were annotated based on NR (non redundant protein sequence database) analysis, respectively. Gene3781 and gene3780 from strain USTB-Y showed 100% identity with dpeH and mpeH from Microbacterium sp. PAE-1. But no phthalate catabolic gene (pht) cluster was found in the genome of strain USTB-Y. The results in the present study are valuable for obtaining a more holistic understanding on diverse genetic mechanisms of PAEs biodegrading Microbacterium sp. strains.

Bacterial Degradation of Bacteriostatic Polyphenols, Tannins

Tannin degradation by bacteria has not been studied much as tannins are commonly known to be bacteriostatic due to enzyme inhibition, substrate deprivation, and the enzyme activity on the bacterial cell wall. However, about a handful of bacteria have been found to tolerate certain concentrations of tannin. This study focuses on isolating and identifying bacteria from decaying portions of tree bark for tannase production and effective catalysis of ester bond hydrolysis in tannins. Different concentrations of commercial tannic acid were used as the sole carbon source on mineral salt medium (MSM) agar plates, to test the maximum tolerable concentrations (MTCs) by the isolates. Tannin degradation was confirmed by a visual reading method and bacterial tannase activity and the biodegradation percentage were determined. One particular isolate was identified to have 50 g/L MTC of tannin, with a tannase activity of 51.61 U/mL that is optimum after 96 hours of incubation. The 16s rRNA sequencing results showed that the isolate belonged to Bacillus genus and the resulting bacterial strain isolate was found to be a new strain of Bacillus subtilis which was submitted to GenBank under the accession number MH330408.

Assessment of Rheological Behaviour of Water-in-Oil Emulsions Mediated by Glycolipid Biosurfactant Produced by Bacillus megaterium SPSW1001.

A screening programme using mineral salt medium supplemented with n-hexadecane resulted in isolating a Bacillus megaterium SPSW1001 which was capable of producing surface active molecules lowering culture medium surface tension to 27.43 ± 0.029 mN/m and interfacial tension to 0.38 ± 0.03 mN/m at 72h and an emulsification index (E24) (85.63%). The biosurfactant product was further used to assess its effects on the rheological characteristics of water-in-oil emulsion prepared with engine oil. Structural characterization of the biosurfactant product by FTIR revealed a C-O-C stretch in sugar moiety and ester carbonyl linkage group between sugar and fatty acids, respectively, while mass spectral analysis revealed its glycolipid nature, with an m/z value of 662.44. The fluid behaviour ofwater-in-oil emulsion showed a non-Newtonian viscoelastic dilatant flow after yielding exemplified appropriately by Herschel-Bulkley model with 100% confidence of fit. The present study is significant in formulation and handling, processing, and transport of emulsion and in understanding flocculation characteristics.

Antimicrobial Profile of Actinomycin D Analogs Secreted by Egyptian Desert Streptomyces sp. DH7.

Egyptian deserts are an underexplored ecological niche, especially the Sinai Peninsula. In our recent study, we explored this extreme environment and shed light on the bioactive capabilities of desert Actinobacteria isolated from Sinai. Fifty desert Actinobacteria were isolated from the Sinai desert using mineral salt media, basal media, and starch casein media. The filtrate of Streptomyces sp. DH 7 displayed a high inhibitory effect against multidrug-resistant Staphylococcus aureus (MRSA) strains. The 16S rDNA sequencing confirmed that isolate DH7 belongs to the genus Streptomyces. The NJ phylogenetic tree showed relatedness to the Streptomyces flavofuscus strain NRRL B-2594 and Streptomyces pratensis strain ch24. The minimum inhibitory concentrations against MRSA were 16 and 32 μg/μL. Chemical investigation of the ethyl acetate extract of Streptomyces sp. DH7 led to the isolation and purification of natural products 1–4. Structure elucidation of the purified compounds was performed using detailed spectroscopic analysis including 1 and 2D NMR, and ESI-MS spectrometry. To the best of our knowledge, this is the first report for the isolation of compounds 1–4 from a natural source, while synthetic analogs were previously reported in the literature. Compounds 3–4 were identified as actinomycin D analogues and this is the first report for the production of actinomycin D analogs from the Sinai desert with an inhibitory effect against MRSA. We indorse further study for this analog that can develop enhanced antimicrobial activities. We confirm that the desert ecosystems in Egypt are rich sources of antibiotic-producing Actinobacteria.

FIPRONIL DEGRADING BACTERIA FROM FRESHWATER ENVIRONMENT

Fipronil is a broad spectrum insecticide, which causes effect on environment and human health. Eight fipronil resistant bacteria were isolated from tank water containing fipronil to study bioremediating efficiency. 16S rDNA sequence analysis of the selected bacterial isolates showed identities of the isolates to Bacillus sp., Bacillus cereus and Comamonas aquatica. The bacterial isolates were capable of tolerating fipronil in the range of 35 to 50 mg L-1. Degradation by three representative isolates after 4, 8 and 12 days of incubation with the initial concentration of 10 and 20 mg L-1 fipronil in mineral salt medium, were in the range of 10.46±1.41 to 94.66±0.46%. Removal was maximum at the concentration of 10 mg L-1 for all the bacterial isolates. For both the 10 and 20 mg L-1 concentration levels, strain C-3 (B. cereus) was found to be highly efficient in remediating fipronil followed by C-1 (Bacillus spp.) and C-6 (C. aquatica). Key words: Fipronil, degradation, Bacillus, Comamonas aquatica, aquatic environment

English

The accidental release of diesel and other hydrocarbon to the environment lead to the pollution of the environment. The search for an environmentally friendly technique for the remediation of such polluted environment is not to be overemphasis. Microorganisms are used in the bioremediation of polluted environments. Hydrocarbon-degrading bacterium isolated from the hydrocarbon exploration site soil of Kukawa North-eastern Nigeria, and was studied for its biodegradation potential of diesel. Culture base techniques using nutrient agar and mineral salt medium supplemented with 1% diesel was used. The bacterium isolate was identified as Enterobacter sp. strain IAA-01.  Identification was carried out using 16S rRNA sequencing and molecular phylogeny analysis using the Phylip software. Gravimetric analysis was conducted to measure the percentage biodegradation of the bacterium for 21 days, and confirmed using Gas chromatography (GC) analysis where the bacterium degraded diesel hydrocarbon 78% after 21 days and total degradation was revealed in GC analysis after 21 days. The results prevailed the ability of Enterobacter sp. strain IAA-01 effectively biodegrade diesel oil.   Key words: Enterobacter sp., biodegradation, gas chromatography, pollution.

Cultivation of Important Methanotrophs From Indian Rice Fields.

Methanotrophs are aerobic to micro-aerophilic bacteria, which oxidize and utilize methane, the second most important greenhouse gas. The community structure of the methanotrophs in rice fields worldwide has been studied mainly using culture-independent methods. Very few studies have focused on culturing methanotrophs from rice fields. We developed a unique method for the cultivation of methanotrophs from rice field samples. Here, we used a modified dilute nitrate mineral salts (dNMS) medium, with two cycles of dilution till extinction series cultivation with prolonged incubation time, and used agarose in the solid medium. The cultivation approach resulted in the isolation of methanotrophs from seven genera from the three major groups: Type Ia (Methylomonas, Methylomicrobium, and Methylocucumis), Type Ib (Methylocaldum and Methylomagnum), and Type II (Methylocystis and Methylosinus). Growth was obtained till 10–6–10–8 dilutions in the first dilution series, indicating the culturing of dominant methanotrophs. Our study was supported by 16S rRNA gene-based next-generation sequencing (NGS) of three of the rice samples. Our analyses and comparison with the global scenario suggested that the cultured members represented the major detected taxa. Strain RS1, representing a putative novel species of Methylomicrobium, was cultured; and the draft genome sequence was obtained. Genome analysis indicated that RS1 represented a new putative Methylomicrobium species. Methylomicrobium has been detected globally in rice fields as a dominant genus, although no Methylomicrobium strains have been isolated from rice fields worldwide. Ours is one of the first extensive studies on cultured methanotrophs from Indian rice fields focusing on the tropical region, and a unique method was developed. A total of 29 strains were obtained, which could be used as models for studying methane mitigation from rice fields and for environmental and biotechnological applications.

Phenol biodegradation and optimisation of cultural and physical conditions by the free cells of newly isolated phenol degrading Alcaligenes sp. AQ5-02

Biological treatment is understood to be the most efficient technique for phenol removal paralleled to other physio-chemical methods. 16s rRNA sequencing for the identification. Mineral salt media with 0.5 g/L phenol as the only carbon source. Temperature, pH, salinity and nitrogen source were optimised. The effects of heavy metals on the percentage of phenol degradation with were tested. Accession number of KT693288 was assigned after identification. Temperature of 25- 35°C, pH 7-8 phosphate buffer were the optimum and ammonium sulphate was established to be the paramount nitrogen source at 0.4 – 0.5 g/L for isolate. The optimised conditions were found reducing the incubation period to 48 h with the ability to tolerate up to 0.2 g/L sodium chloride and degraded 50% and 1.1 g/L phenol. Meanwhile, the isolate AQ5-02 can also effectively degrade 1000 g/L phenol in the presence of heavy metals such as Cr, Zn, and Fe.