The use of black soybeans is limited to the manufacture of soy sauce, which is the case with yellow soybeans which were already popular earlier, therefore this study aims to optimize the analysis of protein and amino acids fermented by R. oligosporus, A. sojae, and their consortium. The research method used was Completely Randomized Design (CRD) and factorial pattern. The data obtained were collected and processed by analysis of variance (ANOVA). If there is a significant difference in the controls, then continue with Duncan’s multiple range test. The results showed that the best mushroom that could increase crude protein was the R oligosporus + A sojae consortium, with an increase of 58.11%, an inoculum dose of 2 grams and a fermentation time of 96 hours. The best research results were then analyzed for amino acids, eighteen types of amino acids were obtained, which consisted of essential and non-essential amino acids, the highest essential amino acid was leucine (3.17%) which gave a savory and delicious taste to soy sauce.