Utilization of Rice Straw Hydrolysis Product of Penicillium sp. H9 as A Substrate of Biosurfactant Production by LII61 Hydrocarbonoclastic Bacteria

This study aims to reveal the prospect of rice straw as a biosurfactant production substrate by hydrocarbonoclastic bacteria. Rice straw can be hydrolysed enzymatically into simple sugar by Penicillium sp. H9. Hydrolysis products are used as growth medium and biosurfactant production by LII61 bacteria. The concentration sugar from hydrolysis product was analyzed by Nelson method. In this study, molasses were used as a comparison substrate in biosurfactant production. The growth response of LII61 bacteria was observed by measuring the turbidity of the culture. Biosurfactant products were evaluated by measuring the emulsification activity (%) and surface tension (mN/m). Acquisition of sugar from rice straw hydrolysis product (RSHP) was 209.25 μg/mL. The optimum growth both of RSHP and molasses substrates were obtained on the 5th day of incubation with a culture turbidity value of OD_λ650 0.201 and OD_λ650 0.157 respectively. The lowest surface tension obtained in culture of RSHP was 48.85 mN/m. It was better than biosurfactant product on the molasses substrate on the 3rd day incubation. However, during the incubation time both substrates did not show emulsification activity. Biosurfactants produced have certain characteristics on variations in pH and temperature.