Solid state fermentation of mixed substrate for l-asparaginase production using tray and in-house designed rotary bioreactor

Abstract

l-asparaginase cover a broad spectrum of industrial application like food, biosensor and chemotherapeutic drug. In the present work, l-asparaginase production was carried out using tray bioreactor and in-house designed, fabricated rotary bioreactor using previously optimized tri-substrate mixture using Aspergillus tubingensis IBBL1. l-asparaginase production by tray bioreactor was performed in temperature controlled chamber. Enzyme production was also performed in newly designed and fabricated rotary bioreactor at room temperature and effect of variables such as substrate loading, mixing events and particle size were evaluated. Maximum l-asparaginase activity of 20.58 U/gds was observed using tray bioreactor with bed height of 1 cm and by applying intermittent mixing strategy at 120 h of fermentation. In case of in-house designed rotary bioreactor, l-asparaginase activity of 19.96 U/gds was obtained with 1.5 kg substrate loading, 3 min delay time of the drum and on rotation for 30 s. These findings demonstrate that in-house designed rotary bioreactor was easy to handle, and has shown comparable results with tray bioreactor. At optimized conditions growth kinetics were studied in tray and rotary bioreactor using various growth model equations. Correlation between growth dynamics and l-asparaginase production was explained by means of Leudeking-Piret model. Results indicate that under the optimized conditions, l-asparaginase can be produced in bulk quantities.