Yang Xiaomin, Huang Tom, Tsao George T
School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Appl Biochem Biotechnol. 2002 Spring;98-100:599-610. doi: 10.1385/abab:98-100:1-9:599.
Inadequate dissipation of heat generated by biologic activities has prevented the use of solid-phase fermentation in large-scale applications. This study deals with the cooling effects of pressure pulsation on solid, porous beds. Pressure pulsation also enhances evaporation of medium moisture, which is also described. Computer software has been developed for on-line control of heat accumulation and moisture loss involving automatic variation in pressure pulsation frequency and airflow direction as well as replenishment of water. Aspergillus niger NRRL3 was cultivated on a moist, solid medium made of wheat bran and ground corncobs to produce cellobiase. During 100 h of fermentation, the maximum temperature inside the solid bed was kept under 40 degrees C, and the medium water content was successfully maintained between 61 and 65%, which was optimal for cell growth. Cells grew heavily on the solid-phase substrate and distributed uniformly. With good on-line control of temperature and moisture, the 12-L fermentor provided a better environment for enzyme production than 250 mL flasks did.
生物活动产生的热量若不能充分消散，会阻碍固相发酵在大规模应用中的使用。本研究探讨了压力脉动对固体多孔床的冷却效果。压力脉动还能增强培养基水分的蒸发，这一点也在文中有所描述。已开发出计算机软件，用于在线控制热量积累和水分流失，包括自动改变压力脉动频率、气流方向以及补充水分。黑曲霉NRRL3在由麦麸和磨碎的玉米芯制成的潮湿固体培养基上培养以生产纤维二糖酶。在100小时的发酵过程中，固体床内的最高温度保持在40摄氏度以下，培养基含水量成功维持在61%至65%之间，这对细胞生长最为适宜。细胞在固相基质上大量生长且分布均匀。通过对温度和水分的良好在线控制，12升发酵罐比250毫升烧瓶为酶的生产提供了更好的环境。
