Investigation of α-amylase production in solid state bioreactor

In this study, rotating drum bioreactor that important one using in the solid substrate fermentation was designed by adapting for semi solid state fermentation and effects of reactor operating parameters on α-amylase production was investigated by experimental design. Ceramic micro diffuser was used to increase oxygen transfer efficiency in the rotating drum bioreactor design. In the α-amylase production studies was used optimum conditions (25 g/l corn bran, 10 g/l yeast extract ve 1 g/l KH2PO4) that determined earlier obtained α-amylase production studies in erlenmayer flasks. The maximum enzyme activty 20,68 U/ml specific productivity 25,36 U/g corn bran.h was obtained in erlenmayer studies. Dissolved oxygen concentration, pH, temperature, oxygen and carbon dioxide at gas outlet was followed online during fermentation in rotating drum bioreactor. Dinitrosalicylic acid method (Bernfeld, 1955) was used for determination of α-amylase activity. Effects of 7 reactor operating parameters, rotation speed, aeration rate, working volume, pore diameter of the diffuser, baffle size, temperature and inoculum size, on the α-amylase production in the rotating drum bioreactor was determined with Plackett-Burman design. According to ANOVA results of Plackett-Burman design, Model is significant as it is seen Model F value (17,46) and very low probality value (0,0075). The effects of rotation speed, aeration rate and baffle size were statistically the significant parameters with low p values (p<0,05). In the validation study that suggested by Plackett-Burman design, enzyme activty 26,64 U/ml and specific productivity 50,86 U/g corn bran.h was obtained in the conditions that rotation speed (18 rpm), aeration rate (2 lpm) and baffle size (4 cm).