Production of pectinase by locally-isolated fungus, aspergillus fumigatus R6 in solid state fermentation for use in kenaf bioretting

Kenaf fibres were produced by removing the pectin, a cementing material that binds the fibres together through the retting process. The traditional method of water retting requires long times and caused water pollution, while dew retting is weather and geographical dependence and produced fibres with low tensile strength. Retting using microbial pectinase is a promising approach as it reduces the times and produces fibres with high tensile strength, furthermore, it is environmental-friendly. The main objective of this study is to determine the efficacy of pectinase produced from a locally isolated fungus strain in kenaf bioretting. Pectinolytic fungi were isolated from the local sources and screened for their pectinase activity qualitatively and quantitatively. The selected pectinolytic fungus with the highest pectinase activity was identified by amplification of ITS region. The cultural conditions for maximum pectinase production from the selected strain were optimised using response surface methodology in solid state conditions,followed by purification using ammonium sulphate precipitation and gel chromatographic methods in order to characterise the pectinase produced. The pectinase produced was applied in kenaf bioretting to evaluate the possibility and efficiency of using pectinase in kenaf retting. A potential pectinolytic strain had been successfully isolated from the kenaf retting tank and was identified as Aspergillus fumigatus R6. Two types of pectinase were produced by A. fumigatus R6, which were polygalacturonase and pectin lyase using rice bran as the substrate in solid state conditions. The optimised cultural conditions for maximum production of polygalacturonase by A.fumigatus R6 was at an initial moisture level of 49.6%, 33°C, and 129 h of incubation time.A. fumigatus R6 polygalacturonase was purified using 60 – 80% ammonium sulphate precipitation and gel filtration chromatographic methods with a purification fold of 2.54 and polygalacturonase yield o