First Report on Bacillus subtilis Producing Cellulase and Phytase Enzymes in Improving the Quality and Nutrient Content of Soymilk Waste through Fermentation

Soymilk waste has potential to be used as feed due to high nutritional value but its utilization is limited by the content of cellulose and phytic acid.To overcome this limitation, fermentation using Bacillus subtilis, a cellulase and phytase producing bacteria was carried out.This study aims to obtain the best fermentation substrate composition and fermentation time that can improve the quality and nutritional content of fermented soy milk waste (FSMW).The substrate was a mixture of Soymilk waste (SW) with cassava leaves (CL), Indigofera leaves (IL) and white leadtree leaves (WLL).The research method used a completely randomized design (CRD) with a 3x3 factorial pattern with 3 replications.Factor A was the substrate of type: A1(80% SW +20% CL), A2(80% SW+20%IL) and A3(80%SW+20WLL).Factor B was the time of fermentation: B1 (2 days), B2 (4 days), and B3 (6 days).The observed variables were protease activity, cellulose activity, crude protein content, crude fiber and nitrogen retention, crude fiber digestibility.The results showed that there was a very significant interaction (P<0.01) between substrate type and fermentation time on cellulose activity, protease activity, crude protein content, crude fiber, digestibility of crude fiber and nitrogen retention.It can be concluded that type of substrate 80%SW+20%CL and a fermentation time of 4 days gave the best results in terms of phytase activity 16.34U/mL, cellulase activity 14.61U/mL, protease 32.95U/mL, phytate content 0.33U/mL, crude fiber 7.04%, crude protein content 29.78%, and nitrogen retention 57.45%, crude fiber digestibility 57.95%.