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 15.3g/kg in untreated SBM, FSBMT reduced phytic acid to below the minimum detectable level (MDL; 0.7g/kg) in 3 samples and FSBM reduced phytic acid to below MDL in 2 samples and to 1.2g/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±0.1g/kg (P<0.05), and phytic acid was reduced from 15.6±0.7g/kg to below MDL (0.7g/kg) in all samples. The FSBM also reduced both oligosaccharides to below MDL (1.0g/kg) in all samples compared with 8.7±1.4g/kg of raffinose and 58.2g/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.