Effect of fermentation with Saccharomyces cerevisiae strain PJ69-4 on the phytic acid, raffinose, and stachyose contents of soybean meal

Two experiments were conducted to determine the effect of submerged fermentation with Saccharomyces cerevisiae strain PJ69-4 on degradation of phytic acid and the oligosaccharides, raffinose and stachyose, in soybean meal (SBM). In Exp. 1, SBM fermented with S. cerevisiae strain PJ69-4 (diploid) (FSBM) was compared with SBM fermented with S. cerevisiae strain PJ69-4 transformed with the PHO5 gene (FSBMT). Compared with 15.3 g/kg in untreated SBM, FSBMT reduced phytic acid to below the minimum detectable level (MDL; 0.7 g/kg) in 3 samples and FSBM reduced phytic acid to below MDL in 2 samples and to 1.2 g/kg in a third. With regard to degradation of phytic acid, FSBMT was not superior to FSBM (P = 0.37 when using MDL as data points). In addition, total P values were not different between treatments (P = 0.12). In Exp. 2, FSBM was compared with nonfermented SBM (control). The FSBM increased total phosphorus from 6.4 ± 0.3 to 7.8 ± 0.1 g/kg (P < 0.05), and phytic acid was reduced from 15.6 ± 0.7 g/kg to below MDL (0.7 g/kg) in all samples. The FSBM also reduced both oligosaccharides to below MDL (1.0 g/kg) in all samples compared with 8.7 ± 1.4 g/kg of raffinose and 58.2 g/kg of stachyose in the control. Results of this study provided preliminary evidence that submerged fermentation of SBM with S. cerevisiae strain PJ69-4 can degrade phytic acid, raffinose, and stachyose to below detectable levels, which may provide nutritional benefits to monogastric animals, particularly weaned pigs.