Bioconversion of agricultural waste hydrolysate from lignocellulolytic mold into biosurfactant by Achromobacter sp. BP(1)5

Rice straw and corn cobs have proven as a promising waste in the bioconversion of biomass into bioproducts. The lignocellulose content found in rice straw and corn cobs has the potential to be hydrolyzed into sugar and used as a carbon source for the growth of microorganisms. This study aims to utilize lignocellulose waste from rice straw and corn cobs for biosurfactant production by Achromobacter sp. BP(1)5. Rice straw and corn cobs were hydrolyzed using Penicillium citrinum H9 4% (v/v) for 6 days. Sugar content was analyzed using the Somogyi-Nelson method with UV–Visible spectrophotometer. Biosurfactants were produced in synthetic mineral water by adding hydrolysate sugar from rice straw and corn cobs for 7 days and evaluated through measurement of surface tension and emulsification activity. Achromobacter's biosurfactant crude extracts were characterized by critical micelle concentration (CMC) value and stability at the variation in pH, temperature, and salinity. Achromobacter sp. BP(1)5 was identified using 16S rRNA. The yields of sugar from rice straw and corn cobs hydrolysis sequentially were 2.260 and 7.880 g/L. The crude biosurfactant from hydrolysate sugar substrate of rice straw and corn cobs had same CMC value that was 6.0 g/L with emulsification activity on kerosene 27.22% and 36.84% respectively. Crude biosurfactant extracts from both substrates were stable on pH 4.0–10.0, temperature 30–70 °C and salinity 0–10% (w/v). This study showed that the agricultural wastes were a cheap material for biosurfactant production, thereby reducing obstacles for biosurfactant production.