The effect of equipping a non-woven fabrics in the fermentor on the production of Acinetobactor radioresistens lipase by batch fermentation.

• Main Authors: SHEN, Chi-chih, 沈啟智
• Other Authors: Chen Teh-liang
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/69706698485346277613

碩士 === 國立成功大學 === 化學工程學系 === 86 === ABSTRACT Acinetobacter radioresistens, a Gram-negative bacterium isolated from the sludge of waste water, produces an extracellular lipase (triacylglycerol acylhydrolase, EC 3.1.1.3), which has a high activity in alkaline pHs. This study intended to examine the effect of equipping a non-woven fabrics in a 2-L tank fermentor on the production of A. radioresistens lipase by batch fermentation.The non-woven fabrics was made from nylon 6 coated with a hydrophobic acrylic resin. It was found that, in the free-cell fermentation with n- hexadecane as the carbon source, the cells entered the exponential growth phase at 75 h, and the maximum lipase yield was 23 U/mL at 102 h. In the non-woven-fabrics system, however, the cells entered the exponential growth phase earlier (at 60 h), the cell concentration attained was higher, and the lipase yield increased to 53 U/mL at 167 h. When the medium was supplemented with 0.1% olive oil, the lipase yield obtained in the free-cell system was 16U/mL at 21 h, owing to excessive foaming occurred at 20 h; in contrast, the lipase yield was 71 U/mL at 84 h if using the non-woven-fabrics system. In addition, excessive foaming was not observed in the latter system. The results obtained with the non-woven-fabrics system were found comparable to that of the free-cell system where gum arabic was added to emulsify n-hexadecane. Based on these findings, the roles of the non-woven fabrics in the fermentation with A. radioresistens can be pictured: (1) it helps the dispersion of n-hexadecane to very fine oil droplets, and thus favors cell growth and lipase production; and (2) it can adsorb surface active agents produced during the fermentation, and thus suppress the foaming.