OPTIMIZING ALPHA AMYLASE PRODUCTION FROM LOCALLY ISOLATED Aspergillus species USING SELECTED AGRO WASTES AS SUBSTRATES
ABSTRACT
α-Amylase are enzymes that are used in the degradation of starch. This study focuses on optimizing the production of α-Amylase using locally isolated Aspergillus japonicus in defined and undefined medium.
Five grams of cocoyam waste, sweet potato waste, wheat waste and plantain peel were utilized as substrates during fermentation for the production of α-Amylase using 1 ml spore suspension as inoculum. The fermentation media contained in g/l (0.8 NaCl, 0.8 KCl, 0.1 CaCl2, 2.0 Na2HPO4, 0.1 FeSO4, 8.0 Fructose, 2.0 NH4Cl). Temperature, pH, sugar content and amylase activity of the culture filtrates were monitored after every 48 hours. For optimization, mycelia was used as inoculum and different inoculum sizes (5%, 10% and 15%) were used for fermentation in a defined medium containing starch as substrate. The effect of urea as nitrogen source on α -Amylase activity was monitored. Different concentrations (2g and 5g) of cocoyam waste and sweet potato waste were also utilized for optimization using 10% inoculum. The effect of temperature and pH on amylase was determined.
Two grams (2g) of sweet potato waste with NH4Cl as nitrogen source, using 10% inoculum gave the highest yield of α-Amylase after 96 hours. The optimum pH and temperature for α -amylase production were pH 5 and 50 oC respectively.
The ability of the amylase to act within an acidic pH suggests that it is stable within a wide range of acidic pH (2 – 6) and its ability to withstand relatively high temperature (40 o C – 60 o C) above the optimum growth temperature of A. japonicus suggests that it is thermo stable. The crude α-Amylase produced from A. japonicus retained 67% of its activity at 60oC.α-Amylase from this fungus has the potential to be utilized for various biotechnological processes. Agro industrial wastes which are often carelessly discarded into the environment causing health hazards can be utilized as cheap and readily available substrate for the production of alpha amylase hence, it is practicable to rid our environment of these hazardous wastes.
Keywords: α-Amylase, Aspergillus japonicus, Optimization, Agro industrial wastes, Environment