Lipopeptide Production from Bacillus sp. GB16 by Using Novel Oxygenation Methods

초록

During lipopeptide (biosurfactant) production by Bacillus sp. GB16, conventional aeration method with antifoam addition was unsucceful due to excessive formation of foam and inhibitory effects of antifoam chemical. A novel integrated method was developed to increase the dissolved oxygen concentration during the microbial production of biosurfactant, lipopeptide. Novel method consisted of (1) adding hydrogen peroxide to the medium, which is then decomposed to oxygen and water by the catalaseand (2) adding vegetable oil and Ca-stearate to the medium as antifoam agent as well as oxygen vector. Dissolved oxygen concentration could be controlled by automatic additionof hydrogen peroxide to the bioreactor. A significant improvement, i.e., suppression of foaming and, therefore, extension of cultivation time over three folds, was obtained while the dissolved oxygen concentration remained stable. This results shows that novel aeration method, i.e.,addition of olive oil, Ca-stearate and hydrogen peroxide) is an effective aeration method when excessive foaming causes the problems such as biosurfactant producing cultivation