Wen Zhiyou, Liao Wei, Chen Shulin
Department of Biological Systems Engineering, Center of Multiphase Environmental Research, Washington State University, Pullman, WA 99164, USA.
Bioresour Technol. 2005 Mar;96(4):491-9. doi: 10.1016/j.biortech.2004.05.021.
Cellulase production by the fungi Trichoderma reesei was studied using dairy manure as a substrate. Data showed that T. reesei RUT-C30 had higher cellulase production than T. reesei QM 9414 and that a homogenized manure, treated by a blender to reduce fiber size, led to higher cellulase production. The cellulase production was further optimized by growing T. reesei RUT-C30 on homogenized manure. The effects of manure concentration, pH, and temperature on cellulase production were investigated with optimal parameter values determined to be 10 g/l manure (dry basis), 25.5 degrees C, and pH 5.7, respectively. Elimination of CaCl2, MgSO4, nitrogen sources (NH4+ and urea) and trace elements (Fe2+, Zn2+, Co2+ and Mn2+) from the original salt solution had no negative influence on the cellulase production, while phosphate elimination did reduce cellulase production. Based on above results, the final medium composition was simplified with manure additives being KH2PO4, tween-80 and CoCl2 only. Using this medium composition and a reaction time of 6-8 days, a maximum cellulase production activity of 1.74 IU/ml of filter paper activity, 12.22 IU/ml of CMCase activity, and 0.0978 IU/ml of beta-glucosidase was obtained. This filter paper activity is the highest ever reported in cellulase production from agricultural wastes.
以奶牛粪便为底物,研究了里氏木霉产生纤维素酶的情况。数据表明,里氏木霉RUT - C30比里氏木霉QM 9414产生的纤维素酶更多,并且经搅拌机处理以减小纤维尺寸的匀质化粪便能产生更多的纤维素酶。通过在匀质化粪便上培养里氏木霉RUT - C30进一步优化了纤维素酶的产量。研究了粪便浓度、pH值和温度对纤维素酶产量的影响,确定最佳参数值分别为10 g/l粪便(干基)、25.5摄氏度和pH 5.7。从原始盐溶液中去除氯化钙、硫酸镁、氮源(铵根离子和尿素)和微量元素(亚铁离子、锌离子、钴离子和锰离子)对纤维素酶的产生没有负面影响,而去除磷酸盐确实会降低纤维素酶的产量。基于上述结果,最终培养基成分得以简化,粪便添加剂仅为磷酸二氢钾、吐温 - 80和氯化钴。使用这种培养基成分和6 - 8天的反应时间,获得了最大纤维素酶生产活性,滤纸酶活性为1.74 IU/ml、羧甲基纤维素酶活性为12.22 IU/ml、β - 葡萄糖苷酶活性为0.0978 IU/ml。该滤纸酶活性是农业废弃物生产纤维素酶中报道的最高值。