Effects of autohydrolysis on rice biomass for reducing sugars production

The current improper disposal methods of rice biomass either by incinerating or open burning has led to an environmental problem due to smoke release to the air. Regarding this issue, much works have been carried out to utilize rice biomass for value-added products but its commercial utilization is hindered due to the lack of clear understanding on the energy conversion that meets the overall environmental friendly standardAbundant of rice biomass production from rice industry has created environmental issues to the surrounding localities primarily due to the inefficient disposal and incineration. Nevertheless, rice biomass has a great potential as a renewable feedstock. Autohydrolysis (a physico-chemical pretreatment method) is one of the options that offers a lot of benefits for the subsequent process such as allow excellent selectivity towards biomass degradation in mild operational conditions. Autohydrolysis pretreatment which were the hydrothermal (HT) and the saturated steam (ST) were analyzed in term of the reducing sugars and the degradation products production. In overall, combined rice biomass in ratio of 3(rice straws):1(rice husks) has been identified to be the best selection with chemical composition of 42.5%, 26.5% and 10.0 % for cellulose, hemicellulose and lignin respectively. This combination of biomass yielded the highest reducing sugars when extracted under HT pretreatment (14.4 g/L) at 210 degrees C for 5 min with 0.58 g/L furfural, 0.27 g/L Hydroxymetylfurfural (HMF), 0.10 g/L total phenolic compounds (TPC). The result obtained by the ST pretreatment is lower about 4.5 times than the HT system. ST needs higher temperature for maximum production of reducing sugars and the production was only 3.19 g/L at 230 degrees C for 15 min with 1.16 g/L furfural, 0.73 g/L HMF, 0.04 g/L TPC. (C) 2019 Elsevier Ltd. All rights reserved.