Production of Acinetobacter radioresistens lipase with repeated fed-batch culture

Acinetobacter radioresistens lipase was produced with repeated fed-batch culture using a balanced medium based on Tween 80 as the carbon source. A constant cell concentration was shown to be a prerequisite to extend the number of repeated cycles, and an adequate cell growth rate was critical for a high lipase yield. The pH-stat feeding was found to sustain cell growth at a rate too high to effect the lipase production. The DO-stat feeding, on the other hand, could be manipulated to allow adequate growth rate for efficient lipase production. The lipase production rate obtained could reach 42,000 U/h in a 2.5 l tank fermentor.