Oxygen uptake rate regulation during cell growth phase for improving avermectin B1a batch fermentation on a pilot scale (2 m3)

Abstract

Avermectin B1a batch fermentation of Streptomyces avermitilis in a 2 m3 fermentor was investigated by oxygen uptake rate (OUR) regulation during cell growth phase. OUR was controlled by adjusting of aeration and agitation. Result showed that OUR strongly affected cell growth and antibiotics production. Avermectin B1a biosynthesis could be effectively enhanced when OUR was stably regulated at an appropriate level in batch fermentation of S. avermitilis. Avermectin B1a yield reached 5568 ± 111 mg/l by controlling maximal OUR between 15 and 20 mmol/l/h during cell growth phase, which was increased by 21.8% compared with the control (maximal OUR above 20 mmol/l/h). The stimulation effect on avermectin B1a production could be attributed to the improved supply of propionic acid and acetic acid, the precursors of avermectin B1a, in the cells. Hence, this OUR control method during cell growth phase may be a simple and applicable way to improve industrial production of avermectin.