Mineral Salt Broth Research Articles

ENVIRONMENTAL DETOXIFICATION POTENTIAL OF AXENIC AND MIXED CULTURES OF BACILLUS SPECIES ON PESTICIDES USING AN IN VITRO BIODEGRADATION ASSAY

Pesticide use is an integral part in global agricultural practice, however, these chemicals have recently been identified as emerging pollutants that impact on ecosystem health and sometimes require remediative intervention. This study assessed the biodegradative ability of species of Bacillus on the organochlorine herbicide, paraquat and the organophosphorus insecticide, dichlorvos. The Bacillus isolates were identified based on their genomic, biochemical and morphological characteristics while the ability of the isolates to degrade the pesticides was determined by monitoring changes in optical density, pH, total viable count and pesticide concentration in in vitro systems over an 18-day period using pesticide-modified mineral salts broth. The two Bacilli isolates were identified as Bacillus crassostreae and Bacillus niabensis. The organochlorine herbicide was more readily utilised by the axenic Bacillus isolates and their mixed culture than the organophosphorus insecticide as evidenced by variations in turbidity and counts. Biodegradation was more effective with the mixed culture than with the axenic cultures. Pesticide degradation levels of 64.26 % – 93.70 % and 70.43 % – 98.20 % were observed for the insecticide and herbicide respectively for both the bacilli and their mixed culture as revealed by gas chromatography analysis. The degradation efficiencies of the two bacilli for both dichlorvos and paraquat showed significant differences from each other and from the mixed culture at 95% confidence interval. The study established the potential of Bacillus crassostreae, Bacillus niabensis and their mixed culture to be employed as inocula in the detoxification of pesticide-contaminated environmental media.

Microbial degradation and transformation of benzo[a]pyrene by using a white-rot fungus Pleurotus eryngii F032

Polycyclic aromatic hydrocarbons (PAHs) are environmentally recalcitrant contaminants formed from naturally or incomplete combustion of organic materials and some of them are difficult to degrade due to their hydrophobicity and persistency. Benzo [a]pyrene (BaP), is one of PAHs that having five fused benzene and reported as mutagenic, carcinogenic and teratogenic compounds. Biodegradation is one of promising techniques due to its relatively low economic cost and microorganism is a natural capacity to consume hydrocarbons. In this investigation, Pleurotus eryngii F032 was grown in 20 mL of modified mineral salt broth (MSB) supplemented with BaP under static and agitated culture. Within 20 days, static culture removed 59% of BaP, whereas agitated culture removed the highest amount (73%). To expedite BaP elimination, the mechanism and behavior of BaP biosorption and biotransformation by Pleurotus eryngii F032 were additionally examined by gas chromatography-mass spectrometer (GC-MS). The optimal conditions for P. eryngii F032 to eliminate BaP were 25 °C, a C/N ratio of 8, pH 3 and 0.2% inoculum concentration. At an initial BaP content of 10 mg/L, more than 50% was effectively eliminated within 20 days under these conditions. Salinity, glucose, and rhamnolipids were the most important factors impacting BaP biodegradation. GC-MS found degradation products such as BaP-3,6-quinone, indicating plausible metabolic routes. Finally, it may be assumed that the primary mechanism by which white-rot fungi eliminate BaP is by the utilization of biotransformation enzymes such as laccase to mineralize the PAHs. Hence, Pleurotus eryngii F032 could be an ideal candidate to treat PAHs contaminated soils.

A new endophyte Monascus ruber SRZ112 as an efficient production platform of natural pigments using agro-industrial wastes

A number of biopigment applications in various industrial sectors are gaining importance due to the growing consumer interest in their natural origin. Thus, this work was conducted to valorize endophytic fungi as an efficient production platform for natural pigments. A promising strain isolated from leaves of Origanum majorana was identified as Monascus ruber SRZ112 produced several types of pigments. The nature of the pigments, mainly rubropunctamine, monascin, ankaflavin, rubropunctatin, and monascorubrin in the fungal extract was studied by LC/ESI–MS/MS analyses. As a first step towards developing an efficient production of red pigments, the suitability of seven types of agro-industrial waste was evaluated. The highest yield of red pigments was obtained using potato peel moistened with mineral salt broth as a culture medium. To increase yield of red pigments, favourable culture conditions including incubation temperature, incubation period, pH of moistening agent, inoculum concentration, substrate weight and moisture level were evaluated. Additionally, yield of red pigments was intensified after the exposure of M. ruber SRZ112 spores to 1.00 KGy gamma rays. The final yield was improved by a 22.12-fold increase from 23.55 to 3351.87 AU g−1. The anticancer and antioxidant properties of the pigment’s extract from the fungal culture were also studied. The obtained data indicated activity of the extract against human breast cancer cell lines with no significant cytotoxicity against normal cell lines. The extract also showed a free radical scavenging potential. This is the first report, to our knowledge, on the isolation of the endophytic M. ruber SRZ112 strain with the successful production of natural pigments under solid-state fermentation using potato peel as a substrate.

Impact of prodigiosin on staphylococcus aureus isolated from acne vulgaris

Acne is a skin disorder characterized by clogged hair follicles and chronic inflammation of the pilosebaceous follicles. A total of one hundred and five acne swabs were collected from patients with acne vulgaris infection at Baghdad's hospitals. For primary identification, 54 (45%) samples had a positive S. aureus culture on Mannitol salt agar (MSA) for 24 hours at 37°C. In addition, four pre-isolated also identified S. marcescens (pigment producers) which were identified by vitek-2 technique were taken for prodigiosin extraction, mineral salt broth with peptone (0.5 percent) was utilized, followed by pigment extraction, partial purification, also pigment measurement by spectrophotometer. Furthermore, using a microtiter plate assay, the bacterial ability to form biofilms was assessed for 20 S. aureus isolates (multidrug resistant isolates). The results revealed that only 8 strong isolates were biofilm producers, while 5 in addition 7 isolates were moderate also weak biofilm producers. The minimal inhibitory concentration of tetracycline also prodigiosin generated by isolated S. marcescens were determined using the broth microdilution technique for S. aureus isolates (S7 also S8). From overnight cultures of S. aureus (S7 also S8), DNA was effectively extracted.

Impact of prodigiosin on staphylococcus aureus isolated from acne vulgaris

Acne is a skin disorder characterized by clogged hair follicles and chronic inflammation of the pilosebaceous follicles. A total of one hundred and five acne swabs were collected from patients with acne vulgaris infection at Baghdad's hospitals. For primary identification, 54 (45%) samples had a positive S. aureus culture on Mannitol salt agar (MSA) for 24 hours at 37°C. In addition, four pre-isolated also identified S. marcescens (pigment producers) which were identified by vitek-2 technique were taken for prodigiosin extraction, mineral salt broth with peptone (0.5 percent) was utilized, followed by pigment extraction, partial purification, also pigment measurement by spectrophotometer. Furthermore, using a microtiter plate assay, the bacterial ability to form biofilms was assessed for 20 S. aureus isolates (multidrug resistant isolates). The results revealed that only 8 strong isolates were biofilm producers, while 5 in addition 7 isolates were moderate also weak biofilm producers. The minimal inhibitory concentration of tetracycline also prodigiosin generated by isolated S. marcescens were determined using the broth microdilution technique for S. aureus isolates (S7 also S8). From overnight cultures of S. aureus (S7 also S8), DNA was effectively extracted.

Bioremediation Ability of the Local Isolate Enterobacter cloacae from Disposal Site

Illegal dumping is a serious problem that needs to be addressed immediately to preserve human health and the environment as if the pollution that arises from it reaches the groundwater, complications of the remediation processes will increase. To decontaminate the organic and inorganic components, bioremediation seems to be the most environmentally friendly and economically viable technique without further treatment as reported by many studies. In this investigation, samples were taken from the soil of the main dumping area in Koysinjaq in Kurdistan Region of Iraq to determine the most potent bacteria to remediate the existed pollutants. The existence of non-essential minerals and organic compounds in the soil sample was detected using X-ray fluorescence device, and ethane and 1,2-dichloroethane solvents separating technique, respectively. Then, from the same samples, three different naturally occurring bacteria were isolated and cultured under optimized conditions then stimulated for a good result. Finally, spectrophotometer was set at wavelength of 600 nm and used to detect the heaviest growth of bacteria after incubating the cultured bacteria on a mineral salt broth medium with the extracted pollutants at pH 7.0 overnight at 32°C. Based on the highest absorbance, the most effective type of bacteria (Enterobacter cloacae) was chosen among others to remediate the organic components in which approximately 90% of them are plastics, medical waste, municipal waste, electrical items, and hydrocarbons, and some heavy metals, for instance aluminum and lead, which were found in the soil.

DETERMINATION OF THE OPTIMAL CONDITIONS FOR LEVAN PRODUCTION FROM THE LOCAL ISOLATE OF Bacillus subtilis Strain AE77

Background: Levan is a promising safe, renewable, and environmentally friendly exocellular homopolysaccharides. It has recently gained increasing research interest because of its significant impact on biotechnology applications due to its biocompatibility and ability to biodegradability. Aim: The study aimed to determine some of the optimal cultural conditions for levan production by studying many parameters affecting production by local isolation Bacillus subtilis (B. subtilis Strain AE77). Methods: B. subtilis Strain AE77 It was obtained from the Department of Food Science/College of Agricultural Engineering Sciences as a local levan-producing isolate isolated from rotten sweets. The Mineral Salts Broth (MSB) medium was approved to study the optimized conditions for levan production. Then precipitation of levan from the fermentation medium. Then the identification of levan with High-Performance Liquid Chromatography (HPLC) technology by estimating the retention time of levan, compared with the standard model produced from the bacterial isolate Erwinia herbicola (E.herbicola). Besides, each of the standard solutions of sugars (fructose, glucose, and sucrose). Results: The study results proved that the polysaccharide produced from this isolate is pure and consists of fructose and is a homopolysaccharide with the HPLC technique. The best levan production was from B. subtilis Strain AE77 using a modified MSB medium of 20% sucrose in a 48 hours incubation period. An inoculum volume of 1×108 cell/ml at a concentration of 2% at an incubation temperature of 35 °C and pH = 7.0 and agitation speed of 150 rpm reached 4.80 g/100ml. Conclusion: HPLC was used to separate, identify and quantify both B.subtilis Strain AE77 and standard levan produced from the bacterial isolate E. herbicola, as well as standard fructose, glucose, and sucrose, respectively. The results showed that levan is a homopolysaccharide consisting of one type of monomer (the fructose sugar units). Conditions for levan production were determined by isolating B. subtilis Strain AE77 in a sucrose medium. The results showed that the optimal medium for production contained 20% sucrose without any nitrogen source, pH7.0, and inoculum volume 1x108 cell/ml at a concentration of 2% at a temperature of 35 °C agitation speed 150 rpm, and incubation period of 48 hours.

Influence of carbon, nitrogen sources, inducers, and substrates on lignocellulolytic enzyme activities of Morchella spongiola

The influence of various carbon, nitrogen sources, inducers, and different agro-wastes on the growth and ligninolytic enzyme activities of Morchella spongiola (MR17) was studied. This fungus has grown well in mineral salts broth containing mannitol as the carbon and yeast extract as the nitrogen sources. In presence of inducers, the growth was inhibited compared to control. The carbon and nitrogen sources and the inducers affected the laccase activity of M. spongiola . Rhamnose and galactose supported the laccase activity more than other carbon sources tested. The manganese peroxidase (MnP) and versatile peroxidase (VP) activities were not detected in the medium amended with different carbon and nitrogen sources. The inducers, ABTS, and veratryl alcohol enhanced the laccase activity more than others. The MnP activity was maximum in wheat straw, followed by rice straw and phenol red. Maximum VP activity was observed in wheat straw, and rice straw, followed by veratryl alcohol. The protein content increased significantly in groundnuts shell and wheat grain substrates inoculated with M. spongiola . Wheat grains and wheat bran served as the most promising substrates with maximum lignocellulolytic activity. The laccase activity was higher in wheat grains and wheat bran, while VP and MnP activities were higher in rice straw and wheat straw. The cellulase activity was much less compared to other enzyme activities in all the substrates. Maximum lignin degradation was observed in wheat straw, followed by wheat bran. The cellulose degradation was significantly higher in groundnuts shell compared to other substrates. The present study results suggest that M. spongiola can utilize these substrates, induce enzyme activities, and have the potential for mushroom cultivation.

MOLECULAR CHARACTERIZATION OF β-AGARASE PRODUCED BY SPHINGOMONAS PAUCIMOBILIS, A MARINE BACTERIUM

Agarases are enzymes that catalyze the hydrolysis of agar. The present study was carried out to isolate the agar degrading microorganisms from marine source. The characterization of agar degrading organism was done by VITEK 2.0 automated instrument, which confirmed the sample as Spinghomonas paucimobilis by a set of 64 biochemical tests. Production of agarase, an extracellular enzyme was done in mineral salt broth with agar and the enzyme was purified by ammonium sulphate precipitation and dialysis. The molecular weight of the enzyme was determined by SDS-PAGE method. Fourier transform infrared spectroscopy analysis was done to authenticate the degree of degradation of agar. The presence of agarase gene was targeted using the required primers and amplified by Polymerase chain reaction. Also the study addresses the problem of solid waste generation of agar waste by any microbiological laboratories and industries.

BIOREMEDIATION OF CRUDE OIL CONTAMINATED SOIL BY HYDROCARBON DEGRADING BACTERIA

Proficiency of hydrocarbon-degrading bacteria useful for eradicating soil pollution stimulated by seepage of petroleum and their derivative substances, therefore, sequestered different bacterial isolates were bear significant merits for utilizing hydrocarbons as an uncommon source of their growth and development. A colorimetric assay was performed at 595 nm wavelength which was subjected to the mineral salt broth with 1% oil (petrol, diesel, and burned out engine oil). This broth having minimum nutrients used by inoculated bacteria in which some isolates were adopted for taking a sufficient amount of either petrol, diesel, or burned-out engine oil as carbon source hence increases its turbidity that was measured in two days time interval up to twelve days of observation. We found that selected isolates were able to degrade burned out engine oil efficiently in contrast to petrol and diesel. At optical density 0.21± 0.13, 0.19±0.08, 0.18±0.09, 0.17±0.12 the result showed by isolatesBI-7, BI-2, BI-4, BI-6goodcompetency to degrade burned out engine oil. On the other hand, maximum diesel and petrol utilized by BI-2 & BI-1 isolate at O.D. 0.09±0.02, 0.05±0.02 was recorded. Most of the bacterial isolates resulted in a positive biochemical test. BI-1 & BI-7 resulted in positive starch hydrolysis test, whereas, all isolates resulted in positive urease test, simultaneously negative results for all isolates obtained when catalase and antibiotic sensitivity test against streptomycin were performed.

Distribution and phenotypic characteristics of common bean (Phaseolus vulgaris L.) nodulating bacteria in diverse soils

ABSTRACT Bacteria were isolated from the root nodules using common bean as a trap host. Growth and morphological characteristics of the bacterial isolates were described on yeast extract mannitol mineral salts agar and broth media. The results showed that over 67% of the isolates produced extracellular polysaccharide with an entire margin and convex elevation. The others differentiated into cream yellow, cream white and milky white colouration with colony area ranging from 0.8 to 26 mm2. The population levels of bacteria nodulating common bean varied in soils and were not affected by the cropping system. However, selected soil parameters greatly influenced the occurrence and distribution of these bacteria. The isolation of indigenous bacteria in all the soils with different cropping systems is an indication that the soils are favourable for nitrogen fixation. Based on the differences in cultural characteristics of the isolates, our data demonstrate the presence of high diversity of bacteria associated with bean nodules.

Biodegradation of Total Petroleum Hydrocarbon by Molecularly Identified Bacteria Isolated From an Oilfield Wastewater in Nigeria

Biodegradation of petroleum hydrocarbon is a complex process that depends on the nature and on the amount of the hydrocarbon present. Many microbial organisms have been shown to possess the capacity to biodegrade various components of hydrocarbon. Hence this study was aimed at assessing the potential of bacterial species isolated from oilfield wastewater to biodegrade total petroleum hydrocarbon in crude oil. Oilfield wastewater was collected from an onshore oil production platform. Standard procedures were observed during collection and microbiological analysis of wastewater samples. Bacteria isolated were identified using conventional and molecular methods. The biodegradation set up was done using six conical flasks containing basal medium of mineral salt broth and crude oil as the source of energy for growth. Bacteria isolated were identified as Acinetobacter species, Enterobacter hormaechei, Myroides odaratimimus and Lysinibacillus species. Flasks of experimental set ups were inoculated with 1ml of individual isolate and mixed culture except the control. The biodegradation of TPH were periodically monitored for 35 days using Gas Chromatography (GC). Total viable counts (CFU/ML) obtained during the experiment ranged from 0-1.8×105, 1.65×105 - 3.2×106, 1.90×106 -1.28×107, 1.52×106 – 8.9×106, 1.13×106 – 1.48×107, 3.4×106 – 2.19×107 in control, Acinetobacter species, Enterobacter hormaechei, Myroides odaratimimus, Lysinibacillus species and the mixed culture treatment options respectively. The initial concentration of TPH at day 1 was 3241.47mg/l. At the end of the experiment (day 35), control, Acinetobacter species, Enterobacter hormaechei, Myroides odaratimimus, Lysinibacillus speccies and the mixed culture treatment options recorded final concentration of 2823.33, 363.72, 383.44, 284.55, 472.70 and 212.21mg/l respectively. Highest percentage removal of 93.5% was observed in the mixed culture while the least of 12.9% was observed in the control; individual species showed significant reduction in TPH with different capability. Results showed that bacteria isolated from oilfield wastewater have the ability to degrade total petroleum hydrocarbon (TPH) and can be used in the clean-up of crude oil contaminated area.

Potentials of mixed cultures of bacteria in the biodegradation of crude oil

This study aimed at exploring the potentials of mixed cultures of bacteria isolated from crude oil polluted sites for the biodegradation of crude oil. Mixed cultures of five bacterial isolates: Pseudomonas aeruginosa, P. putida, P. fluorescens, Bacillus subtilis and Micrococcus luteus were used for the crude oil biodegradation study. The degrading ability of the mixed cultures were assessed for duration of 28 days on a shaker at 300 rpm and at ambient temperatures (28±2 oC) in a mineral salt broth amended with 1% crude oil. Parameters used to assess the degradative abilities were pH, bacterial load, and residual crude oil contents. The result showed a significant increase in the bacterial count as the biodegradative study progressed while the pH and residual crude oil content decreased. The consortium of P. aeruginosa, P. putida, P. fluorescens, B. subtilis and M. luteus (CB1) was able to achieve reduction of crude oil to 92.4% followed by P. aeruginosa, P. putida, and P. fluorescens (CB2) with reduction of 89.5% in 28 days of biodegradative study. It is concluded from this study that the consortium CB1 were effective crude oil degraders. Thus, they are recommended for use in the bioremediation of polluted soils. Key words: Polluted soils, Crude oil, Consortia, Bacteria, Biodegradation

Biodegradation of Crude Oil-Polluted Soil by Bacterial Isolates from Nigeria

Biodegradation of crude oil-polluted soils by bacterial isolates was carried out experimentally, to determine the ability of bacterial isolate to utilize and detoxify crude oil-polluted soils. Three soil samples were collected from crude oil-polluted sites of Owazangboko, Abia State, Aguleri-otu, Anambra State and Obi-igbo, Rivers State, Nigeria. Microbiological analysis and physico-chemical analysis were carried out in the Microbiology Laboratory of Chukwuemeka Odumegwu Ojukwu University, Uli. Physico-chemical analysis was carried out to determine the pH, moisture content, water holding capacity and total organic carbon of the soil samples. Microbiological analysis was carried out using serial dilution and spread plate methods to determine the total viable count, enumeration of hydrocarbon utilizing bacteria (HUB) was done using vapour phase method on mineral salt agar monitored at the wavelength of 600nm for 5 days. Adaptation test was carried out and monitored for 5 days using mineral salt broth containing 1ml and 2ml of sterile crude oil separately. A consortium of six effective isolates was taken for the biodegradation of the crude oil, which was monitored for 14 days. Biochemical tests were carried out on the isolates. Polymerase chain reaction (PCR) technique was used to confirm the identity of the isolates. Gas chromatographic flame ionization detector (GC-FID) was used to monitor the amount of the residual total petroleum hydrocarbon after the biodegradation study. Results of physic-chemical analysis showed; pH value of 3.7– 6.6, moisture content 1.6 – 4.4., water holding capacity 28.0 – 32.0., total organic carbon 3.4 – 7.1. Results of total viable count were in the range of 7.1×106 - 5.9×1010. Results of vapour phase method ranged from 0.16 – 0.66. Adaptability test revealed values, 0.11 – 0.54. Biochemical test results revealed Bacillus spp., Pseudomonas spp., Serratia spp., Micrococcus spp., Arthrobacter spp., Proteus spp., Shigella spp. PCR results gave the identity of the organisms to be Lysinibacillus spp. M2c, Serratia marcescens Mb4, Bacillus aerius TPM-23, Proteus mirabilis LS-3 and a new unidentified bacterium. TPH concentrations were in the range of 582.67 mg/l – 123.67 mg/l for Lysinibacillus spp. M2c and Serratia marcescens Mb4, 682.65 – 203.85 mg/l for Bacillus aerius TPM-23and 753.32 mg/l – 324.77 mg/l for Proteus mirabilis LS-3 and the new unidentified bacterium. The effect of bacterial growth across the days showed a p-value of 0.000 less than the α-value 0.01, this concluded that the growth of the bacteria across the days was significant for both vapour phase test and adaptability test. From this study it is evident that Serratia marcescens Mb4 and Lysinibacillus spp. M2c could be used to effectively treat crude oil-polluted environment.

Degradation of polycyclic aromatic hydrocarbons (phenanthrene and pyrene) by the ligninolytic fungi Ganoderma lucidum isolated from the hardwood stump

BackgroundDue to progress in science and technology, several harmful polycyclic aromatic hydrocarbons are synthesized and released into the environment. In the present investigation, a phenanthrene- and pyrene-degrading white rot fungi Ganoderma lucidum strain CCG1 was isolated from the Janjgir Champa district of Chhattisgarh, India, and then the degradation of phenanthrene and pyrene was estimated by high-performance liquid chromatography.ResultsIt was found that G. lucidum able to degrade 99.65% of 20 mg/L of phenanthrene and 99.58% of pyrene in mineral salt broth after 30th day of incubation at 27 °C. G. lucidum produced significant amounts (p < 0.0001) of ligninolytic enzymes (Laccase, lignin peroxidase and manganese peroxidase) in the phenanthrene- and pyrene-containing mineral salt broth. G. lucidum produced maximum 10,788.00 U/L laccase, 3283.00 U/L Lignin peroxidase and 47,444.00 U/L Manganese peroxidase enzymes in the presence of phenanthrene and produced maximum 10,166.00 U/L laccase, 3613.00 U/L lignin peroxidase and 50,977.00 U/L manganese peroxidase enzymes in the presence of pyrene. Therefore, G. lucidum will be a potent phenanthrene and pyrene degrader from the environment.

Optimization of Arginine deiminase production from a local higher productive isolate Enterococcus faecium M1

Arginine deiminase (ADI) is an important enzyme in many biological applications and a cancer treatment agent, recently increasing attention is focused to choose a higher productive strain from different bacterial sources. Eighty nine Enterococcus isolates were obtained from 215 samples (20 clinical UTI specimens, 52 human stool specimens, 6 soil and 11 from sewage water), fifty seven isolates were ADI producer. Twenty five isolates were more active in enzyme production, fourteen of them were identified as E. faecium and 11 isolates were E. faecalis. E. faecium isolate M1 obtained from UTI was the most efficient in ADI production, the specific activity of ADI produced from this isolate was 2.64U/mg protein. The effect of culture medium (Mineral salt broth) components on ADI production and other cultural conditions were determined to find the optimum conditions for enzyme production. The maximum ADI production was achieved when the medium was supplemented with 20mM arginine, 1% sucrose, 1% casein, pH 7.5 and incubated at 37ºC for 18 hours. Under these conditions, the specific activity of ADI was 5.1U/mg protein. By concluding, the present study was designed to select ADI higher productive isolate and optimum culture conditions for increasing the production of this enzyme in order to use it as a potent cancer treatment agent after purifying and characterizing it in the future.

Microbial assisted (pseudomonas sp.) production of novel bio-surfactant rhamnolipids and its characterisation by different spectral studies

The production and characterisation of rhamnolipids bio-surfactant obtained by the strain P19 of pseudomonas sp. was investigated. With regard to the carbon and nitrogen sources, several media were investigated to enhance the production of the bio-surfactant. Primarily the bacteria was isolated from the soil by using mineral salt (MS) broth [Peptone – 0.5g, KH2PO4 – 0.7g, NaH2PO4 – 0.9g, NaNO3 – 2g, MgSO4·7H2O – 0.4g, CaCl2·2H2O – 0.1g]; trace elements: 2mL solution of a mixture containing FeSO4.7H2O – 2g, MnSO4 – 1.5g, (NH4)6Mo7·4H2O – 0.6g in 1L of distilled water; along with 2g/L d-glucose as carbohydrate source. The production of rhamnolipids by the bacteria was confirmed by C-TAB-methylene blue agar plate assay. The selected strain was identified on the basis of Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) of the ribosomal protein. The isolated bio-surfactant was characterised by HRMS and NMR spectroscopic studies. The CMC of purified rhamnolipids was calculated using the UV–Vis method and found to be 34.2mgL−1. The optical micrograph and HR-TEM images invoked the formation of miceller nano-aggregates of the bio-surfactant in aqueous solution.

Degradation of polycyclic aromatic hydrocarbon (pyrene) using novel fungal strain Coriolopsis byrsina strain APC5

Coriolopsis byrsina strain APC5, white rot fungi was isolated from Surguja district of Chhattisgarh, India, which was able to degrade 96.1% of pyrene with the help of their ligninolytic activity. C. byrsina produced a significant amount of ligninolytic enzyme upto p < 0.0001 significant level in the pyrene containing mineral salt broth. Different physical parameters like pH (3.0–8.0), temperature (15–55 °C) and salinity (10 g L−1, 32 g L−1) were optimized for the efficient degradation. The highest degradation of pyrene and enzyme production was found on pH 6 at 25 °C temperature. The pyrene degradation was analyzed by High performance liquid chromatography and functional group modification of pyrene degraded metabolites were characterized by Fourier transform infrared spectroscopy and identified by Gas chromatography-mass spectroscopy. The metabolic intermediate compounds are identified, such as pyruvic acid, benzoic acid, benzoic acid 2-hydroxy pentyl ester, phenanthrene, pthalic acid diisopropyl ester, 4, 5 di hydroxy pyrene. Degradation of pyrene was also examined in in-vivo condition and 51.85% degradation was investigated in soil, On the basis of this study, C. byrsina strain APC5 can be used as potential pollutant degrader from the environment after successful field trial.

Microbial detoxification of eleven food and feed contaminating trichothecene mycotoxins

BackgroundContamination of agricultural commodities with multiple trichothecene mycotoxins, produced by toxigenic Fusarium species, is a food safety issue, which greatly affects grain production and marketing worldwide. Importantly, exposure to multiple trichothecenes may increase toxicity in animals due to their synergistic and/or additive effects. To address the problem this study aimed to achieve a novel biological trait capable of detoxifying various food and feed contaminating trichothecenes under aerobic and anaerobic conditions and wide range of temperatures.ResultsA highly enriched microbial consortium (called DX100) capable of transforming eleven trichothecenes to significantly less toxic de-epoxy forms was achieved after prolonged incubation of soil microbial culture with 200 μg/mL deoxynivalenol (DON). DX100 demonstrated de-epoxidation activity under aerobic and anaerobic conditions, a greater range of temperatures and around neutral pH. The consortium contains 70% known and 30% unknown bacterial species, dominated by Stenotrophomonas species. Probably novel bacteria including strains of Stenotrophomonas and Alkaliphilus-Blautia species complex could be involved in aerobic and anaerobic de-epoxidation of trichothecenes, respectively. DX100 showed rapid and stable activity by de-epoxidizing 100% of 50 μg/mL deoxynivalenol at 48 h of incubation and retaining de-epoxidation ability after 100 subcultures in mineral salts broth (MSB). It was able to de-epoxidize high concentration of DON (500 μg/mL), and transformed ten more food contaminating trichothecenes into de-epoxy forms and/or other known/unknown compounds. Microbial de-epoxidation rate increased with increasing trichothecene concentrations in the broth media, suggesting that DX100 maintains a robust trichothecene detoxifying mechanism. Furthermore, the nature of microbial de-epoxidation reaction and inhibition of the reaction by sodium azide and the finding that bacterial cell culture lysate retained activity suggests that certain cytoplasmic reductases may be responsible for the de-epoxidation activity.ConclusionsThis study reports the enrichment procedure for obtaining an effective and stable microbial consortium DX100 capable of de-epoxidizing several food contaminating trichothecene mycotoxins. DX100, which has de-epoxidation ability under wide range of conditions, represents a unique enzymatic source which has great industrial potential for reducing contamination of foods/feeds with multiple trichothecenes, and minimizing their synergistic/additive cytotoxic effects on consumer health.

Estimation of decrease in cancer risk by biodegradation of PAHs content from an urban traffic soil.

The role of preferential biodegradation in the reduction of cancer risk caused by polycyclic aromatic hydrocarbons (PAHs) has been studied. A consortium of microorganisms isolated from aged oil refinery exposed soil was used to degrade 13 PAHs content extracted from an urban traffic site soil. The biodegradation arranged in a batch process with a mineral salt broth, where PAHs were the sole carbon source. 70.46% biodegradation of the total PAHs occurred in an incubation period of 25days. Sequential or preferential biodegradation took place as the lower molecular weight (LMW) PAHs were more prone to biodegradation than that of the higher molecular weight (HMW) PAHs. Microorganisms from the isolated consortia preferred the simpler carbon sources first. The relatively higher carcinogenicity of the HMW PAHs than that of the LMW PAHs leads to only 40.26% decrement in cancer risk. Initial cancer risk for children was 1.60E-05, which was decreased to 9.47E-06, whereas, for the adults, the risk decreased to 1.01E-05 from an initial value of 1.71E-05. The relative skin adherence factor for soil (AF) turned out to be the most influential parameter with 54.2% contributions to variance in total cancer risk followed by the exposure duration (ED) for children. For the adults, most contributions to the variance in total cancer risk were 58.5% by ED and followed by AF.