Utilization of Soybean Cooking Drain

Abstract

With the purpose to utilize the soybean cooking drain from miso factories, cultivation of molds was investigated employing 66 strains including Aspergillus, Monascus, Penicillium and Paecilomyces. Aspergillus oryzae FRI-23 gave the best results with respect to cell yield and enzyme activity in the mycelia. Good growth of the mold was obtained by starting the cultivation in the medium at pH 6, and addition of carbon source such as glucose was more effective than addition of nitrogen source such as ammonium sulphate. The mass doubling time and the specific growth rate were determined 3.5hr and 0.2hr^-1, respectively. AS the result of cultivation, COD of the soybean cooking drain was reduced to the level of 15% of the initial concentration (20, 000ppm). Higher enzymatic activities of acid proteinase (pH 3), neutral proteinase (pH 6 and 7.5) and peptidase in mycelia were seen at logarismic phase of the growth. Crude protein and nucleic acids contents of the dried mycelia were approximately 40% and 4%, respectively. As the result of the addition of the cultivated raw mycelia to miso as the source of protein and enzymes for acceleration of the fermentation, the amounts of free glutamate and flavor of the miso increased during fermentation of the miso.