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.

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.

Biotransformations of HBCDs by Rhodococcus Strain Stu-38 and Identification of Transformation Products

1, 2, 5, 6, 9, 10-Hexabromocyclododecanes (HBCDs) are new brominated flame retardants causing serious environmental pollution. Dozens of degradative bacteria have been found with capacity to transform HBCDs. In the present study, an aerobic functional bacterium Rhodococcus strain stu-38 was isolated from enriched culture of mangrove sediment using HBCDs as carbon source. This strain could stereoselectively transform HBCDs, the removal rate was α-＞γ-＞β-HBCD in the mineral salt medium, but was β-＞α- and γ-HBCD in the growth medium, and it selectively transformed γ- HBCD in the seawater. Transformation rate of strain stu-38 was lower than other functional strains, however, seven potential debrominated products of HBCDs were identified by using GC-MS. These debrominated products, included dibromocyclododecadiene, bromocyclododecadienol and bromocyclododecatriene were formed through reductive debromination, hydrolytic debromination and dehydrobromination. Overall, Rhodococcus sp. stu-38 diastereoisomer-specifically transformed HBCDs to various debrominated products in the different cultural media, which highlighted the complicated stereoselective biotransformation of HBCDs.

Low-Density Polyethylene Film Biodegradation Potential by Fungal Species from Thailand

Accumulated plastic waste in the environment is a serious problem that poses an ecological threat. Plastic waste has been reduced by initiating and applying different alternative methods from several perspectives, including fungal treatment. Biodegradation of 30 fungi from Thailand were screened in mineral salt medium agar containing low-density polyethylene (LDPE) films. Diaporthe italiana, Thyrostroma jaczewskii, Collectotrichum fructicola, and Stagonosporopsis citrulli were found to grow significantly by culturing with LDPE film as the only sole carbon source compared to those obtained from Aspergillus niger. These fungi were further cultured in mineral salt medium broth containing LDPE film as the sole carbon source for 90 days. The biodegradation ability of these fungi was evaluated from the amount of CO2 and enzyme production. Different amounts of CO2 were released from D. italiana, T. jaczewskii, C. fructicola, S. citrulli, and A. niger culturing with LDPE film, ranging from 0.45 to 1.45, 0.36 to 1.22, 0.45 to 1.45, 0.33 to 1.26, and 0.37 to 1.27 g/L, respectively. These fungi were able to secrete a large amount of laccase enzyme compared to manganese peroxidase, and lignin peroxidase enzymes detected under the same conditions. The degradation of LDPE films by culturing with these fungi was further determined. LDPE films cultured with D. italiana, T. jaczewskii, C. fructicola, S. citrulli, and A. niger showed weight loss of 43.90%, 46.34%, 48.78%, 45.12%, and 28.78%, respectively. The tensile strength of LDPE films cultured with D. italiana, T. jaczewskii, C. fructicola, S. citrulli, and A. niger also reduced significantly by 1.56, 1.78, 0.43, 1.86, and 3.34 MPa, respectively. The results from Fourier transform infrared spectroscopy (FTIR) reveal an increasing carbonyl index in LDPE films culturing with these fungi, especially C. fructicola. Analysis of LDPE films using scanning electron microscopy (SEM) confirmed the biodegradation by the presence of morphological changes such as cracks, scions, and holes on the surface of the film. The volatile organic compounds (VOCs) emitted from LDPE films cultured with these fungi were analyzed by gas chromatography-mass spectrometry (GC-MS). VOCs such as 1,3-dimethoxy-benzene, 1,3-dimethoxy-5-(1-methylethyl)-benzene, and 1,1-dimethoxy-decane were detected among these fungi. Overall, these fungi have the ability to break down and consume the LDPE film. The fungus C. fructicola is a promising resource for the biodegradation of LDPE which may be further applied in plastic degradation systems based on fungi.

DETERMINATION OF THE OPTIMUM CONDITIONS FOR BIOSURFACTANT PRODUCTION BY LOCAL ISOLATE OF LACTOBACILLUS PLANTARUM AND EVALUATE ITS ANTIMICROBIAL ACTIVITY

Eighty five local isolates of Lactobacillus sp. which were isolated from different sources and identified by biochemical test then subjected to the primary and secondary screening processes to select the active Lactobacillus sp. isolate for biosurfactant production. Among the isolates screened, twenty six isolates with maximum for tests in primary screening were selected for secondary screening. It has been found that Lactobacillus sp. ADK2 had the highest productivity of the biosurfactant. The selected isolate with highest level of biosurfactant activity was identified as Lactobacillus plantarum ADK2 according to PCR technique. The optimum conditions of biosurfactant production by isolate Lactobacillus plantarum ADK2 using submerged fermentation were obtained in the synthetic mineral salt medium (MSM) and natural BCDFTM medium the best production medium separately, 1.5% (lactose and egg) as the best carbon source, 2% meat extract and 3.5% Pease as nitrogen source, temperature 30 °C for two media and pH 5 with pH 3 in MSM and BCDFTM respectively, after 96 hr and 72 hr in MSM and BCDFTM respectively of incubation period.

PRODUCTION OF LIPASE BY IMMOBILIZED BACILLUS THURINGIENSIS AND LYSINIBACILLUS SPHAERICUS AND THEIR BIODEGRADATION POTENTIAL ON DIESEL

This study reported production of lipase by immobilized Bacillus thuringiensis. Bacteria isolates were screened on Bushnell-Hass Mineral Salt medium containing 1% v/v Diesel for oil degradation. The potent isolates were identified using 16S rRNA as Bacillus thuringiensis. The isolates were immobilized in gelatin matrix and cultured for lipase production in a submerged medium. The crude lipase extracted was used for degradation of Diesel. Optimum degradation of Diesel 41.4% was obtained by lipase from Immobilized Bacillus thuringiensis and 31.6% for Lysinibacillus sphaericus at pH 7 and 35 in 20 days. GC-MS analysis was carried out to show the compounds degraded after 20 days. This study therefore presented the use of immobilized bacterial lipase in degradation of Diesel as a simple and effective approach.

Identification of Carbofuran and Paraquat Degrading Microorganisms from Soil

Introduction: Increased rates of pesticide misapplication and follow-on concerns on public health have become subjects of countless distress. The occurrence of pesticides in soils could result in modifications in soil physical, chemical as well as biological properties hence the need for ways to reduce such impacts. Research Gap: Insufficient literatures on extensive identification of pesticides’ degraders from non-impacted soils. Existing literatures are restricted to a particular microbial group (bacteria or fungi). Aim: The study aimed at isolating, characterizing and testing bacteria, moulds, yeasts and actinomyces from soil for the biodegradation of pesticides. Place and Duration of Study: The study was carried out at the Department of Environmental Management and Toxicology, Federal University of Petroleum Resources, Effurun and Federal Institute of Industrial Research, Oshodi, Lagos, Nigeria/ four months. Methodology: Carbofuran and Paraquat degrading microorganisms were isolated from a non-pesticides impacted soil using mineral salt medium (MSM). The MSM composed in grams per liter: K2HPO4, 4.8; KH2PO4, 1.2; NH4NO3, 1.0; MgSO4 7H2O, 0.2; Ca(NO3)2 .4H20, 0.4, and Fe(SO4)3, 0.001 supplemented with 2 mM Carbofuran or Paraquat as the only carbon source. The ability of the microbial isolates to utilize Carbofuran and Paraquat was screened on MSM containing 150 part per million of the pesticides as the only carbon source. The isolates were identified using the analytical profile index (API), microscopic and macroscopic characteristics. Results: Bacterial species identified were Bacillus, Pseudomonas, Kocuria, Enterobacter, Chryseobacterium, Corynebacterium, Acinetobacter, Paenibacillus, Lerclercia and Proteus. Actinomyces were Actinomyces isrealii, Actinomyces naeslundi, Actinomyces viscosus 1, Actinomyces meyeri and Actinomyces viscosus 2. Yeast isolates were Candida stellatoidea, Candida krusei and Saccharomyces cerevisiae while moulds were Talaromyces, Cladosporium carionii and Curvularia species. Conclusion: These findings indicated that Carbofuran and Paraquat degrading organisms are readily extant in soils and can be used to facilitate the removal of these pesticides from such polluted environments.

Evaluating of chlorpyrifos-degrading by bacterial strains in mineral salt minimum and in the soil

Four bacterial strains degraded chlorpyrifos, isolated from agricultural soil, were used as a source of bacteria to investigate their ability to decompose chlorpyrifos in mineral salt minimum and the soil. Barrientosimonas humi C4.3 was investigated for the decomposition of chlorpyrifos in this strain on different days (10, 20 and 30 days of culture) as supplemented and not supplemented TSB. At the same time, another experiment was carried out to evaluate the chlorpyrifos etherification of B. humi C4.3 and the four strains of Achromobacter xylosoxidans C3.1, B. humi C4.3, Microbacterium sp. C8.9, Staphylococcus pasteuri C9.2 in a soil environment. The experiment was carried out including 3 treatments, each treatment was repeated 3, two soil types (sterile soil and non-sterile soil) and bacteria (single bacteria and four bacterial species). The results showed that, in the same culture period of 30 days incubation, biodegradable chlorpyrifos of B. humi C4.3 in the mineral salt medium was more effective (63.07% biodegradable chlorpyrifos) than when grown in soil (21.4% biodegradable chlorpyrifos). Also, biodegradable chlorpyrifos of B. humi C4.3 that was cultured in sterile soil was higher than in non-sterile soil.

Biodegradation of 2-methylisoborneol by enzyme separated from Pseudomonas mandelii

As a kind of odorous substance, 2-methylisoborneol (2-MIB) is difficult to be degraded naturally. Some isolated strains of bacteria can degrade 2-MIB effectively. In this study, a strain of bacteria which can remove 2-MIB from drinking water efficiently was obtained from activated carbon in a filter, and was identified to be Pseudomonas mandelii based on 16S rRNA gene sequence analysis. Pseudomonas mandelii was not sensitive to the initial concentration of 2-MIB, and could tolerate a rather high concentration of 2-MIB. The best growth conditions for this degrader were 25–35 °C and initial pH of 7. The concentration of 2-MIB in mineral salt medium was reduced from 2 mg/L to 471.9 μg/L by Pseudomonas mandelii in 20 d after incubation. Nineteen bands of degrading enzyme were isolated from Pseudomonas mandelii, one of which was identified as a NAD-dependent dehydratase. It was found that 2-methyl-2-bornene was the metabolite in the presence of both the Pseudomonas mandelii and the isolated enzymes, indicating that NAD-dependent dehydratase might be involved in the biodegradation process or cooperate with other enzymes in the metabolic process to complete the dehydration process of 2-MIB.

Polyethylene Biodegradation Potentials of Pseudomonas aeruginosa and Micrococcus sp. Isolated from Waste Dumps and Farmlands in Nsukka, Enugu State, Nigeria

Background: Low Density Polyethylene (LDPE) are plastic materials extensively used in packaging, constituting recalcitrant environmental pollutants that defy natural degradation processes. Aim: This study isolated bacteria from a Nigerian environment and assessed their potential for LDPE biodegradation. Methods: Using standard procedures, Bacteria were isolated from polythene samples collected from farmlands and waste dump sites in Nsukka metropolis. Mineral salt medium (MSM) was prepared, with LPDE as sole carbon source, and used for isolation. Optical density (OD600 nm) was used to study bacterial growth on LDPE as sole carbon source as proof of biodegradation. Both organisms demonstrated steady growth on LDPE over time. Results: Pseudomonas aeruginosa and Micrococcus sp. were identified based on morphological and biochemical characteristics. Ability to grow on LDPE as a sole carbon source was studied as evidence of polyethylene biodegradation. Organisms were inoculated into MSM and incubated at 37°C and 50°C for 15 days. Maximum growth was recorded after 15 days of incubation for both organisms. P. aeruginosa and Micrococcus sp. showed steady growth at 37°C as well as 50 ⁰C. Micrococcus sp. recorded highest growth; 0.324 nm and 0.312 nm at 37°C and 50°C respectively, after 15 days. Similarly, P. aeruginosa recorded highest growth of 0.40 nm and 0.258 nm for 37°C and 50°C respectively. LDPE degradation increased with increase in time. Conclusion: This study demonstrates the enormous polyethylene-degrading potentials of P. aeruginosa and Micrococcus sp. isolated from Nsukka, Nigeria.