Effect of pressure on germination rate of Verticillium lecanii spores.

• Main Authors: Yi-Chien Hsieh, 謝依蒨
• Other Authors: Chee-Shan Chen
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/23040977954762966256

碩士 === 朝陽科技大學 === 應用化學系碩士班 === 95 === This research studied the solid state fermentation of Verticillium lecanii spore production for its potential application in the field of bio-insecticide. A fermentor using pressurized air for oxygen supply, heat and water balances was investigated. Operational parameters such as medium composition, inoculation strategy, pressure and humidity were studied. Results showed that using pressurized air system has the benefit of removal of heat and carbon dioxide generated from fermentation during the depressurizing stage. While moderate pressure helps in transferring oxygen into the solid state medium, the fermentation system tends to loose water during the pressurizing / depressurizing cycle. The addition of rice husk significantly improved mass transfer. The viability of spores produced was found to be seriously affected by the repeated pressurizing / depressurizing cycle at 30 psi (germination rate reduced to 66%). Time length of each pressurizing / depressurizing cycle also affected, to a lesser extent, the germination rate. The rate of pressure change, however, was found to be most important and should be controlled to be less than 0.2 psi/sec. Germination rate higher than 90% could be maintained at this rate of pressure change. Experiments also showed that water loss due to heat could be compensated by humidifying inlet air with mist generated by a supersonic vibration unit.