Optimization of solid‐state fermentation condition for crude protein enrichment of rice bran using Rhizopus oryzae in tray bioreactor

Enhancement of crude protein content in rice bran with the solid‐state fermentation method in tray bioreactor using Rhizopus oryzae FNCC 6011 has been investigated. This research aimed to optimize the fermentation condition using the response surface methodology (RSM). The central composite design (CCD) with three independent variables, including substrate thickness (1 to 3 cm), fermentation temperature (28 to 32 °C), and nutrient concentration of KH2PO4 (2 to 6 g/L) used to determine the crude protein enrichment. The quadratic model has successfully described the effect of variable interactions on responses very well as indicated by the F value and p‐value are 11.20 and 0.0041, respectively. The multiple correlation coefficients (R2) of 0.9438 indicated that 94.38% of the model data has approached the actual data with a deviation of 5.62%. The interaction between the variable substrate thickness and the fermentation temperature is the most influential variable on the crude protein enrichment of rice bran, indicated by the highest F value of 24.08 and the lowest p‐value of 0.0027. The highest protein increase of 62.51% was obtained at 2 cm substrate thickness, fermentation temperature of 30 °C, and KH2PO4 concentration of 4 g/L.

Optimization of BS4 Enzyme production with Different Substrate Thickness and Type of Trays

BS4 enzyme that is produced from solid substrate fermentation (SSF) on coconut cake with Eupenicillium javanicum BS4 in tray bioreactor has been applied as a feed additive. It increases the nutritional value of animal feedstuff. The BS4 production on SSF may be influenced by the better aeration through the perforated trays or by the thinner substrate. The aim of this research is to optimize the production of BS4 with different substrate thicknesses and types of trays. The trial was carried out using a factorial randomized design (2x2x3) with 6 replicates. The first factor was the type of trays: i.e., non-perforated and perforated tray. The second factor was the thickness of the substrate: i.e., 1.5 and 3.0 cm, while the third factor was the duration of fermentation: i.e. 5, and 7 days. The variables observed were moisture content, dry matter loss (DML), mannanase and saccharification activities, soluble protein content, their specific activities, and yield. Statistical analysis showed no interactions between the three factors, but there were interactions between types of trays and substrate thicknesses, as well as type of trays and incubation times on the mannanase activity and yield of mannanase. The results showed that DML was observed on day 7 were around 31.43- 36.89. The highest mannanase activity was observed on the non-perforated tray with 3 cm thickness on day 7. The saccharification activity towards palm kernel meal was better in the non-perforated tray on day 7 but not influenced by The yield value of mannanase and saccharification activities on a non-perforated tray with 3.0 cm thickness on day 7 was also the highest. Based on energy efficiency and the cost of production, it can be concluded that the optimum condition to produce the BS4 enzyme was observed in the non-perforated tray with 3 cm thickness and fermented for 7 days.

Kinetic of Biomass Growth and Protein Formation on Rice Bran Fermentation Using Rhizopus oryzae

Rice bran is the outermost part of the rice grain wrapped in rice husks. Rice bran contains macro and micro nutrients that are bound to fibers that affect psychochemical properties when used in food products. The purpose of this study was to increase the nutritional value of rice bran with solid state fermentation using Rhizopus oryzae FNCC 6011 in tray bioreactor at 30°C for 120 h. The results showed an increase in protein, fat and ash content by 58.5%, 124.5%, and 18.6%, respectively, while carbohydrate and fiber content decreased respectively by 25.6% and 51.2%. The deceleration model successfully depicts the profile of biomass growth and improved protein. The kinetic parameters obtained k, A, and YPX were 0.0536/h, 5.2537, and 0.1821 g/g, respectively.