State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China; Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, China.
Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, China.
Bioresour Technol. 2019 Nov;291:121841. doi: 10.1016/j.biortech.2019.121841. Epub 2019 Jul 17.
Soybean dregs are restricted as feed additives because they contain anti-nutrient factors. Herein, soybean dreg was bio-transformed by solid-state fermentation (SSF) using a poly γ-glutamic acid (γ-PGA) producing stain Bacillus amyloliquefaciens NX-2S. The maximum γ-PGA production of 65.79 g/kg was reached in a 5 L fermentation system while the conditions are 70% initial moisture of soybean dregs with addition of molasses meal, 12% inoculum size, 30 °C fermentation temperature, initial pH of 8, and 60 h fermentation time. Meanwhile, continuous batch fermentation was proved feasible. After SSF, the anti-nutritional factors such as trypsin inhibitor, phytic acid and tannin were reduced by 98.7%, 97.8%, and 63.2%, respectively. Compared with unfermented soybean dregs, adding fermented soybean dregs to feed increased the average weight gain of rats by 15.6% and reduced the ratio of feed to meat by 11.3%. Therefore, this study provided a feasible strategy for processing soybean dregs as feed additive.
豆粕由于含有抗营养因子而被限制作为饲料添加剂。在此，采用产聚γ-谷氨酸（γ-PGA）的地衣芽孢杆菌 NX-2S 通过固态发酵（SSF）对豆粕进行生物转化。在 5 L 发酵系统中，当豆粕初始水分含量为 70%，添加糖蜜粉，接种量为 12%，发酵温度为 30°C，初始 pH 值为 8，发酵时间为 60 h 时，γ-PGA 的最大产量达到 65.79 g/kg。同时，连续批发酵被证明是可行的。固态发酵后，胰蛋白酶抑制剂、植酸和单宁等抗营养因子分别降低了 98.7%、97.8%和 63.2%。与未发酵的豆粕相比，添加发酵豆粕可使大鼠的平均体重增加 15.6%，饲料与肉的比例降低 11.3%。因此，本研究为将豆粕作为饲料添加剂进行加工提供了一种可行的策略。
