ABSTRACT
Consistent fossil fuel exploration and production leads to environment deterioration. Oil spills make agricultural soil infertile and also pollute groundwater which becomes harmful to humans and other organisms. In this study, we explored ecofriendly method for biodegradation of petroleum hydrocarbons from crude oil contaminated agricultural soil using hydrocarbon utilizing bacterial consortium (HUBC). Soil microcosms were designed to study degradation efficiency of HUBC for petroleum hydrocarbons present in crude oil. Residual petroleum hydrocarbons were measured using gas chromatography. Bioaugmentation studies (with HUBC) showed 83.50±2.05% degradation of petroleum hydrocarbons contaminants at 60 days in crude oil contaminated agricultural soil microcosm. The hydrocarbon utilizing bacterial count in bioaugmented soil microcosm was noted to be 0.60±0.02×108 CFU/g at 60 days i.e. at the end of experiment, which was noted to be 4.90±0.07×107 CFU/g at the start of experiment. Ability of the consortium (used in the presented study) to survive in artificially contaminated agricultural soil microcosm and to degrade petroleum hydrocarbons effectively in soil microcosm conditions shows its potential to be used for bioremediation of agricultural soil and its restoration.
ABSTRACT
Pullulan is one of the most essential exopolysachharides (EPS) of α(Glucan) units in which most commonly α(1→4) linkage predominate. The Aureobasidium pullulans is the key microorganism for pullulan production. A major problem with Aureobasidium pullulans is coproduction of melanin along with pullulan. In this study, we looked for a novel strain having potential to produce pullulan without producing melanin and to evaluate various process parameters for its production. A total of 20 isolates were obtained from the soil sample but out of these only one strain that produced a significant amount of pullulan (71.39 mg/mL). This strain was identified as Micrococcus luteus (GenBank accession no KX261689) based upon the 16S rRNA sequencing. The characterization of pullulan was done with Enzymatic (Pullulanase) hydrolysis study and FTIR analysis. More than 85% hydrolysis of pullulan by pullulanase enzyme had also indicated the presence of α(1→6) and α(1→4) linkages in the structure of pullulan. Various evaluated values of different parameters for production of pullulan were found to be pH: 6.0, Temperature:35˚C, rpm: 250, Incubation time: 5 days. A Central Composite Design (CCD) was implemented in which peptone showed more effect than other factors in pullulan elaboration.
ABSTRACT
Dye effluents from textile units with azo compounds, heavy metals viz., Cu, Cd, Zn, Ni and Pb and other highly suspended solids contaminate the environment by releasing toxic and potential carcinogenic substances into the water bodies. Though there are various chemical and physical processes available for removal of such contaminants, their efficiency still needs improvement. In this study, we explored the efficiency of zinc oxide (ZnO) nanocomposites on the removal of dyes from synthetic and textile industrial effluents. ZnO nanoparticles were synthesized by chemical reduction method using zinc nitrate and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results have shown the average size of nanoparticles to be ~20 nm. Size and shape of ZnO nanoparticles were confirmed by SEM. ZnO nanocomposite was prepared by incorporating ZnO nanoparticles with chitosan. Under optimum process conditions of initial dye concentration of 600 ppm, the ZnO nanocomposite dosage of 0.9 mg/mL at 30°C and pH 6, ZnO nanocomposite exhibited 99% of dye removal from synthetic and textile industrial effluent. However, process conditions were slightly differed when industrial effluent was used. The results suggested that ZnO nanocomposite could be used as an adsorbent for removal of dyes from industrial wastewater.
ABSTRACT
Petroleum reservoir is an ecosystem having extreme environmental conditions of temperature, pressure and salinity. They possess highly anoxic conditions. Major microbial communities present in this environment include fermentative bacteria, sulphate reducing bacteria (SRB), syntrophic bacteria and methanogens. Phylogenetic diversity of microorganisms as well as their ecological role play an important role in the petroleum reservoir ecosystem. Past and present efforts to characterize microbial communities in oil field ecosystem by culture or cultivation-dependent and -independent approaches are discussed with highlights of microbial ecology of petroleum oil reservoir ecosystem(s). Novel strategies used to study culture independent diversity of microorganisms using metagenomic techniques have also been narrated.