Conventional methods of eliminating water from crude oil such as the chemical injection have both economic and environmental impacts; thus, this study proposed an economic and environmentally friendly demulsifier. The bottle test method was used to study the performance of the natural extract and commercial demulsifier on a crude oil sample. The GC-MS profile of the extract was in agreement with previous reports on composition of oil extracted from rice bran using hexane, ultrasound assisted extraction and conventional solvent extraction with ethanol. Varying degrees of saturated and unsaturated fatty acids as well as retention times as observed, was a function of total time of scanning, according to NIST08 library of mass spectra. The performance of the demulsifier was expressed in terms of percentage of water separated from 100 ml samples of the oil samples. For both the demulsifiers, the performance increased with increase in volume of the demulsifier, separation time and operating temperature. The extracted demulsifier performed better than the chemical demulsifier under all the experimental conditions adopted in this study. Based on the parametric evaluation, it was observed the results from software corroborated the results obtained from experiments in terms of the observations of the combined effect of temperature and volume which showed the most significant influence on demulsification of the emulsified crude. The highest efficiency of the bio-demulsifier was obtained with a volume of 5 mL of the extract, at a temperature of 70°C and separation time of 60 min. A water separation efficiency of 85.6% was obtained as compared to the chemical demulsifier, which gave an efficiency of 80.2%.

Aims: Laccases are diphenol oxidases that have numerous applications in biotechnological processes. In this work, the production of fungal laccase using organic and inorganic feed substrates in submerged static fermentation was investigated. Study Design: One-factor-at-a-time strategy was adopted to optimize the cultural parameters for enhanced laccase production. Place and Duration of Study: Department of Microbiology, Faculty of Science, University of Port Harcourt, Nigeria, between October 2014 and November 2015. Methodology: A total of nine fungal isolates were obtained from wood decaying sites of University of Port Harcourt forest areas and subjected to laccase screening with 2,2-Azinobis-3-ethyl(benzthiazoline-6-sulphonate) (ABTS). The influence of medium components using the basal medium at pH 5.0 as base was evaluated and these cultural parameters include carbon sources (glycerol, rice bran, glucose and ground orange peelings), nitrogen sources (yeast extract, potassium nitrate, peptone and ammonium chloride), metal ions (copper sulfate and manganese sulfate) and inducer compounds (ABTS, Tween 80 and soya oil). Time course study was conducted with the unoptimized and optimized cultural medium. Results: Out of nine cultures tested, seven were found to be laccase-positive with isolates CF-1 and CF-2 being the best potential cultures. Isolate CF-1 which had the highest laccase activity was identified as Pleurotus ostreatus and was chosen for further studies. Ground orange peelings (0.1% w/v) and NH₄Cl (0.1% w/v) were the most suitable carbon and nitrogen source for laccase production by the fungus. Maximum laccase production was obtained with Cu²⁺ at a concentration of 0.05%w/v among other metal ions. Soya oil at concentration of 0.05% (v/v) was the best inducer of the enzyme. The highest laccase production was achieved at an Initial pH 4.5. Under optimal culture medium, the maximum laccase activity was determined to be 7.21 U ml^-1 on the 7th day of cultivation; which was approximately three times higher than that in basal medium (2.5 U ml^-1). The results obtained indicate that the extracellular laccase production is dependent on various cultural parameters. Conclusion: One-factor-at-a-time strategy adopted in this study proved that the optimum conditions enhanced laccase production by three folds using orange peelings. The results obtained are very interesting since orange peelings are common agricultural wastes in several countries and imply that their re-utilization in the production of enzymes would help solve pollution problems caused by their improper disposal. In addition, Pleurotus ostreatus having shown promise for laccase production using low-cost lignocellulosic substrates could be suggested as a prospective candidate for higher laccase production for several biotechnological applications.

Insolubility challenges have reduced the efficiency and rate of environmental bioremediation of hydrophobic pollutants occurring in hydrocarbons, soil and water environments. As biosurfactants, sophorolipids possess the unique capacity of activity at the interface of immiscible liquids or solid-liquid phases, thus reducing surface and interfacial tensions through emulsification, dispersion, foaming and wetting, with advantages of stability, ecological acceptability and ability to be produced from renewable and cheaper substrates. In light of the above, this study was aimed at assessing the hydrocarbons emulsification and heavy metals detoxification efficiencies of sophorolipid biosurfactants produced from harvested mushrooms and yeasts isolated from a hydrocarbon contaminated site in Obohia, Abia State, Nigeria. Isolates were cultured on an optimized media fortified with agro-industrial waste substrates of rice bran and food industry waste oil as hydrophilic and hydrophobic sources of carbon, respectively. However sophorolipids production from the yeast, Candida bombicola, was confirmed by the emulsification index after 24 h, surface tension (ST), FT-IR spectroscopy and GC-MS analyses. Solubilization of selected hydrocarbons (used engine oil, kerosene, unused engine oil, diesel and crude oil) was observed with percentage emulsification activities at 60.7, 56.7, 46.9, 44.8 and 40.0 %, respectively. Furthermore, various concentrations of chromium, lead, zinc, copper and cadmium salt solutions incubated with culture supernatants of sophorolipids for 24 h were observed to remove 43.41% chromium from a 10mg/l salt solution and 23.11( Cr), 9.93 ( Pb), 7.29 (Zn), 4.96 (Cu) and 15.71 (Cd) from the highly toxic 70 mg/L salt solutions upon analysis via atomic absorption spectrometry. Our results indicate that sophorolipid biosurfactants could enhance the rate of bioremediation efficiency by emulsifying, solubilizing and detoxifying environmental contaminations of hydrocarbons and heavy metals respectively. Sophorolipids of agro-industrial waste origin possess good surface-active properties that can facilitate the solubilization, dispersion and desorption of hydrophobic environmental contaminants for microbial uptake and bioremediation.