Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA.
Appl Biochem Biotechnol. 2012 May;167(1):109-21. doi: 10.1007/s12010-012-9665-0. Epub 2012 Apr 18.
To increase the value of coproducts from corn ethanol fermentation and soybean aqueous processing, distiller's dried grains with solubles (DDGS) and soybean cotyledon fiber were used as the substrates for solid state fermentation (SSF) to improve feed digestibility. Aspergillus oryzae, Trichoderma reesei, and Phanerochaete chrysosporium were chosen as they produce desirable enzymes and are widely used in SSF for feed. The results showed that the cellulase and xylanase activities were significantly increased after 7 days of fermentation, and cellulose and hemicellulose degradation was also greatly increased. When soybean fiber was used as SSF substrate, the maximum activities of the cellulase and xylanase were 10.3 and 84.2 IU/g substrate (dry weight basis) after SSF treatment, respectively. However, the enzyme activities were relatively low in DDGS, and the growth of the three fungi was poor. The fungi grew better when soybean cotyledon fiber was added to DDGS, and cellulase and xylanase activity increased with the increase of soybean fiber content. Porosity was identified as an important factor for SSF because the addition of inert soybean hull alone improved the fungi growth significantly. These data suggest that the nutritional value of DDGS and soybean cotyledon fiber as monogastric animal feed could be greatly enhanced by SSF treatment.
为了提高玉米乙醇发酵和大豆水提物的副产物价值，利用酒糟（DDGS）和大豆子叶纤维作为固态发酵（SSF）的基质，以提高饲料的消化率。选用米曲霉、里氏木霉和黄孢原毛平革菌，因为它们能产生理想的酶，并且广泛应用于 SSF 饲料。结果表明，发酵 7 天后，纤维素酶和木聚糖酶活性显著提高，纤维素和半纤维素降解也大大增加。当大豆纤维作为 SSF 基质时，经过 SSF 处理后，纤维素酶和木聚糖酶的最大活性分别达到 10.3 和 84.2 IU/g 基质（干重基础）。然而，在 DDGS 中，酶活性相对较低，三种真菌的生长较差。当向 DDGS 中添加大豆子叶纤维时，真菌生长得更好，纤维素酶和木聚糖酶活性随着大豆纤维含量的增加而增加。孔隙率被确定为 SSF 的一个重要因素，因为单独添加惰性大豆皮就可以显著改善真菌的生长。这些数据表明，通过 SSF 处理可以大大提高 DDGS 和大豆子叶纤维作为单胃动物饲料的营养价值。
