Cassava pulp hydrolysis under microwave irradiation with oxalic acid catalyst for ethanol production

Microwave irradiation is an alternative method of starch hydrolysis that offers a rapid process. the aim of this research was to improve microwave-assisted hydrolysis of cassava pulp by using oxalic acid as a catalyst. suspension of cassava pulp in 0.5% oxalic acid (1 g/20 ml) was subjected to microwave irradiation at 140-230°c for 5 minutes,with 4 minutes of pre-heating. one gram of fractured activated carbon made of coconut shell was added into a number of suspensions that were subjected to the same conditions of microwave irradiation. the soluble fraction of the hydrolysates was analyzed for its total soluble solids,malto-oligomer distribution,glucose content,ph value,and formation of brown compounds. the effects of the combined severity parameter at a substrate concentration of 5-12.5% on the glucose yield were also evaluated. the highest glucose yield (78% of dry matter) was obtained after hydrolysis at 180°c without activated carbon addition. heating above 180°c reduced the glucose yield and increased the ph and the formation of brown compounds. the use of activated carbon in microwave-assisted acid hydrolysis of cassava pulp reduced the glucose yield,but suppressed the formation of brown compounds. the highest glucose yield (70-80% of dry matter) was attained at a severity parameter of 1.3-1.5. © 2014 published by itb journal publisher.