Chukwuma S. Ezeonu, Olawale Otitoju, Ikechukwu N.E. Onwurah, Chigozie M. Ejikeme, Ositadinma C. Ugbogu, Ephraim N. Anike


Aspergillus fumigatus (AF) and Aspergillus niger (AN) were isolated from consortia of other microorganisms from an over 8 months decomposing rice husk dump using potato dextrose agar (PDA). Pure strains of individual Aspergillus species were obtained and identified. Measured quantities of freshly processed rice husk in Mandle’s medium were heat pre-treated in an autoclave at 121oC for 20 minutes, cooled and inoculated with the fungi. Seven days fungal treated rice husks were assayed for the following biomass content: Carbohydrate (total sugar), simple sugar, non-reducing sugar, cellulose, lignin and protein. Saccharomyces cerevisae from baker’s yeast and from palm wine were introduced into some of the fungal treated rice husks and fermented for 7 days for their bio-ethanol content. All samples data were in triplicate before analysis. The data were statistically analyzed using analysis of variance (ANOVA- SPSS 16 ) data package). Differences were considered significant at p < 0.05. Data were presented in percentages. The result obtained in the work showed that rice husks treated with Aspergillus fumigatus had the highest cellulose (45 ± 3.31 %), hemicelluloses (31 ± 3.00 %), carbohydrate (19.52 ± 10.05 %), reducing sugar(2.60 ± 0.30 %) and non reducing sugar (16.92 ± 9.75 %) yields; ethanol from palm wine yeast yield was 6.60 ± 0.48 % while bakers yeast yielded 5.60 ± 0.42 % ethanol. Diculture combination of Aspergillus fumigatus and Aspergillus niger (AF+AN) gave the greatest total lignin value of 33.34 ± 3.14 %. The values obtained in the various bio-fuel and biomass components of fungal monocultures of Aspergillus fumigatus (AF) and Aspergillus niger (AN) treated rice husk had no significant difference in increase of product yield at P > 0.05. However, there were significant differences in product yield between the fungal treated rice husks and those of the controls at P < 0.05. The optimized condition involved in bio-product estimation showed that 30oC and pH 5 gave the maximum carboxymethylcellulase activity in crude enzyme of products respectively. It was discovered that heat pre-treated rice husks with additional hydrolysis using the fungi (Aspergillus fumigatus and Aspergillus niger) showed increase in biomass and biofuel yields.

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DOI: http://dx.doi.org/10.19044/esj.2014.v10n18p%25p

European Scientific Journal (ESJ)


ISSN: 1857 - 7881 (Print)
ISSN: 1857 - 7431 (Online)


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