Optimization of D-amino acid oxidase production by Trigonopsis variabilis using glucose syrup from cassava as carbon source

Abstract

Abstract. Rusli Z, Suryadi H, Wibisana A. 2018. Optimization of D-amino acid oxidase production by Trigonopsis variabilis using glucose syrup from cassava as carbon source. Bioteknologi 15: 26-32. Glucose syrup from cassava (GSC) contains glucose as the main sugar suitable for an economical and efficient production of D-amino acid oxidase (DAAO) by Trigonopsis variabilis. The aim of this study is to optimize the DAAO production by T. variabilis using GSC as the carbon source via response surface methodology (RSM) with Face-centered Central Composite Design (FCCD). In the first step, the effects of six factors (concentration of GSC and DL-alanine, pH, temperature, incubation time, and inoculum concentration) were screened to obtain the significant factors on DAAO production by Plackett-Burman design. As a result, the incubation time, the concentration of GSC and DL-alanine showed to be significant factors for DAAO production (P<0.05). These factors were then optimized using RSM with FCCD. The optimized RSM results demonstrated that a quadratic polynomial model was found suitable to define the relation between the incubation times, concentration of GSC and DL-alanine parameters. Moreover, the observed high R² value (0.9782) confirms a strong evaluation of the experimental data. The optimum condition for DAAO production is as follows: GSC and DL-alanine concentration was 12.3% and 0.3%, respectively, and the culture incubation time was 56.1 hours. Using this condition, we got a DAAO activity of 195.38 U/g dry weight of yeast.