Optimization of Fermentation Conditions for α-L-arabinofuranosidase Production by Aspergillus oryzae PT4

Introduction: This study aimed to optimise the fermentation conditions for the production of α-L arabinofuranosidase by Aspergillus oryzae PT4 obtained from agrowaste. This enzyme has significant industrial applications, including biofuel production, food processing, and animal feed improvement, owing to its role in the hydrolysis of complex plant polysaccharides. Methodology: Aspergillus oryzae PT4, obtained from potato peels, was identified using morphological and molecular techniques. Fermentation optimisation was conducted using agro-waste substrates and refined carbon sources such as copra meal, palm kernel cake, soybean meal, Xylan, Carboxy Methyl Cellulose, Locust Bean Gum, Xylose and Arabinose. Various environmental factors, including pH, temperature, inoculum size, and incubation time, were systematically varied using the one-factor-at-time (OFAT) approach. Enzyme yields were monitored by assaying α-l-arabinofuranosidase using p-nitrophenyl-α-l-arabinofuranoside as the substrate. Results: The 18sRNA sequence of Aspergillus oryzae PT4 was phylogenetically similar to that of A. oryzae UCB039. The organism produced the highest enzyme in the presence of xylan (refined carbon) and copra meal (complex carbon) with enzyme activities of 29.33±0.49 U/gds and 25.83±0.39 U/gds, respectively. However, these values were significantly different (P = 0.05). The carbon source, copra meal, required no additional nitrogen for optimal production (57.25 ± 0.21 U/gds) of this enzyme by the isolate. Solid-state fermentation with copra meal as an agro-waste substrate yielded the highest enzyme activity (80.99±6.60 U/gds) under optimised conditions of pH 5.0, a temperature of 30°C, moisture content of 100% v/w, inoculum size of 4% v/w and a 7-day incubation period. Conclusion: This study successfully optimised the production of α-L-arabinofuranosidase using a low-cost substrate (copra meal) and demonstrated its potential for sustainable industrial applications.