COMPARATIVE ANALYSIS OF BIOSURFACTANT PRODUCTION FROM BREWERY EFFLUENT USING PSEUDOMONAS SPECIES (PSEUDOMONAS AERUGINOSA AND PSEUDOMONAS FLUORESCENS)

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Date
2015-05
Authors
KOLAWOLE, OLADIMEJI TAYO
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Abstract
The increasing demand for surfactant calls for an alternative to the chemically synthesized surfactant, which poses a lot of threat to the environment due to bio-accumulation of its undegradable toxic component. Accumulation of industrial and domestic waste also threatens the environment by contributing unfriendly gases and toxic compounds, therefore due to tighten environmental regulations and increasing need to protect the ecosystem, alternatives to chemically synthesized surfactant, which is biosurfactant, is a necessity. Biosurfactants are biodegradable and stable at extreme temperatures and pH. Brewery effluent is an excellent substrate for the production of biosurfactant. Pseudomonas aeruginosa and Pseudomonas fluorescens isolated from soil produced glycolipid biosurfactant from brewery effluent. The brewery effluent used as substrate had chemical oxygen demand of 15,000mg/l, dissolved oxygen of 2.9mg/l and biological oxygen demand of 1.8mg/l. Screening both isolates for their ability to produce biosurfactant, both were positive for drop collapse assay and hemolytic test. For the oil displacement assay 28mm and 23mm were observed for Pseudomonas aeruginosa and Pseudomonas fluorescens respectively. Fermentation process was observed for 168hrs and readings of surface tension and optical density was taken every 24hrs. Three factors were evaluated in the fermentation of the effluent which include; incubation period, pH and temperature. For the incubation period 31.30mN/m and 33.76mN/m was observed for Pseudomonas aeruginosa and Pseudomonas fluorescens respectively. For ionic concentration ranging from pH 4.0 to 10.0, pH 7.0 had the least surface tension reading with 31.87mN/m and 33.04mN/m for Pseudomonas aeruginosa and Pseudomonas fluorescens respectively. Among the pH considered, difference in surface tension was insignificant, indicating a stable biosurfactant. For the temperature ranging from 25oC to 80oC, temperatures 30oC and 35oC had the least surface tension reading though with minimal difference across the temperatures range. The growth of the cells used in fermentation was monitored using the colorimeter at 600nm. The peak growth was generally recorded at 72hrs and peak growth highest at 1.07 for he growth of the cells used in fermentation was monitored using the colorimeter at 600nm. The peak growth was generally recorded at 72hrs and peak growth highest at 1.07 for incubation factor. The best growth for pH factor was observed at pH 5.0 and 7.0. The control set-up for fermentation had the least surface tension reading as compared to all other factors with 30.87mN/m and 32.87mN/m for Pseudomonas aeruginosa and Pseudomonas fluorescens respectively. The application of the biosurfactant produced was tested by checking it ability to emulsify hydrocarbons (diesel, premium motor spirit, kerosene and olive oil). Also applying the various factors (incubation period, pH and temperature), they all showed stable emulsion in 24hrs excluding pH4 with poor or no emulsion formation. Ionic concentration 10.0 had the highest emulsion formation within 24hrs with 87% to 80%. Biosurfactant extracted from Pseudomonas aeruginosa induced fermentation was 3.6g/l and 2.8g/l from Pseudomonas fluorescens. The spectra analysis (FT-IR) of the extract revealed the probable presence of glycolipid biosurfactant as the surface active compound produced by both isolate. From statistical evaluation of data collected, neither of the isolates performed better than the other but shows that there is a significant association between growth rate and surface tension reduction (biosurfactant production)in both isolates at P=0.005
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A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF A MASTER DEGREE IN MICROBIOLOGY DEPARTMENT OF MICROBIOLOGY FACULTY OF SCIENCE AHMADU BELLO UNIVERSITY, ZARIA NIGERIA.
Keywords
COMPARATIVE ANALYSIS,, BIOSURFACTANT PRODUCTION,, BREWERY EFFLUENT,, PSEUDOMONAS SPECIES,, (PSEUDOMONAS AERUGINOSA,, PSEUDOMONAS FLUORESCENS),
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