The objective of the study was to determine the factors affecting post-fermentative nutritional content resulting from soybean fermentation by Bacillus subtilis. Conditions for the nutritionally optimal fermentation of soybeans by B. Subtilis were varied to analyze the overall nutrient content change. The conditions included: (1) pH, (2) fermentation temperature, (3) fermentation time, and (4) bacterial density. Experimental results show the highest concentration of lipids at a pH 6.0, temperature of 33 °C, and 60 h fermentation time. Carbohydrates were highest at pH 7, 28 °C and 48 h, and protein content yielded highest at pH 8, 28 °C, and 60 h of fermentation. Bacterial density had no statistically significant affect on nutritional content (p > 0.05). Optimization of fermentation conditions contributes to increased biomass during fermentation to increase reaction yield of the desired product. Therefore, this research is important at the industrial level to increase production efficiency and reduce energy consumption.