Chen Xiong, Chen Shouwen, Sun Ming, Yu Ziniu
National Key Laboratory of Agricultural Microbiology, National Engineering Research Centre of Microbial Pesticides, Huazhong Agricultural University, Wuhan 430070, PR China.
Bioresour Technol. 2005 Nov;96(17):1872-9. doi: 10.1016/j.biortech.2005.01.033. Epub 2005 Mar 5.
Solid-state fermentations (SSF), using swine manure as the basis of a solid substrate, were carried out for high yield of poly-gamma-glutamic acid (gamma-PGA) by Bacillus subtilis CCTCC202048. Fermentation medium and process parameters were optimized through three orthogonal array designs. The optimal medium consisted of 62.3% (w/w, dry weight basis) swine manure, 25.0% soybean cake, 5.0% wheat bran, 5.0% glutamic acid, 2.5% citric acid and 0.2% MnSO4.H2O. The optimal process parameters were 15.0 g medium with initial moisture content 60% and initial pH 9.0 in 250 ml flask, inoculation at mid-log phase with a 4% inoculum level and cultivation for 48 h at 37 degrees C. The average-PGA yield (6.0%) in triplicate under optimal conditions was obtained on the laboratory scale while it was 4.5% at compost experiment. These would lay a foundation for lessening the pollution of swine manure, increasing fertilizer efficiency and exploring a late-model organic fertilizer that retains water and nutrients.
以猪粪为固体底物基础，进行固态发酵（SSF），以通过枯草芽孢杆菌CCTCC202048高产聚γ-谷氨酸（γ-PGA）。通过三个正交试验设计对发酵培养基和工艺参数进行了优化。最佳培养基由62.3%（w/w，基于干重）猪粪、25.0%豆饼、5.0%麦麸、5.0%谷氨酸、2.5%柠檬酸和0.2%硫酸锰一水合物组成。最佳工艺参数为：在250毫升烧瓶中加入15.0克培养基，初始水分含量60%，初始pH值9.0，在对数中期接种，接种量为4%，在37℃下培养48小时。在实验室规模下，最佳条件下三次重复的平均γ-PGA产量为6.0%，而在堆肥实验中为4.5%。这些将为减少猪粪污染、提高肥料效率以及探索一种保水保肥的新型有机肥料奠定基础。
