Production of extracellular protease enzyme by aspergillus niger / Siti Khairunnisa Daud

Project paper (Bachelor of Chemical Engineering in Biotechnology) -- Universiti Malaysia Pahang - 2012

Bibliography: p. 54-61

The research aimed to study the production of extracellular protease enzyme using potato peel extract as the additional carbon source for Aspergillus niger. Proteases are catalytically functioned to hydrolyze or breakdown the peptide bonds of proteins. Proteases are found to be used in many biotechnological processes and industrial applications such as in baking industry for gluten development, dairy industry as milk-clotting agents and pharmaceutical industries. Wastes from the agricultural and food industry gives out serious problem and as an action of initiative, those wastes can be used up and converted into value added materials as well as cost-effective substrates for fermentation of extracellular protease enzyme. Furthermore, in order to produce high yields of protease enzymes, the optimization of parameters is considered vital since it takes a long time and expensive to be optimized conventionally. This study was performed by using Response Surface Methodology (Central Composite Design). Aspergillus niger had been chosen as biomass while potato peel from the agricultural and food industry was used as additional substrate in this study. The potato peel will be grinded and blended with peel:water ratio of 1:3. The fermentation study will be take place in the shake flasks and several parameters were optimized for higher protease enzyme activity. Three factors were taken into considerations which were the pH of the fermentation medium (pH 3.5 – pH 7.5), the substrate concentration (20 g/l – 60 g/l) and the agitation speed (100 rpm – 300 rpm). From OFAT analysis, protease enzyme showed the optimum activity at pH 5.50, 40 g/l and 200 rpm with 1.23 U/ml, 1.57 U/ml and 1.38 U/ml, respectively while RSM results depicted that the optimum values of each parameter were 5.5 for pH, 40 g/l of substrates concentration and 200 rpm of agitation speed which gave out the optimum protease activity of 2.4563 U/ml. As the conclusion, RSM is the best tool used to identify the correlation between controlled independent factors and observed dependent responses and the utilization of waste as the fermentation substrates is highly acceptable due to its higher protease activity. For future study, it is recommended for an optimization of potato peel extracts concentration as the main carbon source, the application of genetic engineering in the enzyme production, further scale up protease production using a bioreactor and purification and toxicology studies on protease enzyme for further used by human, food and pharmaceutical industries.