Bioconversion of cellulose to α-1,4-glucan

Summary

A biochemical procedure to convert β-1,4-glucosepolymer (cellulose) to α-1,4-glucosepolymer (starch) has been studied in vitro. Cellulose was hydrolyzed to cellobiose by cellobiose producing cellulase which was isolated from culture filtrates of Cellvibrio gilvus. A 90% hydrolysation was obtained after 12 h at 37 °C. The product was found to contain only cellobiose when examined paperchromato-graphically. The second step was the conversion of cellobiose to glucose 1-phosphate by cellobiose phosphorylase, purified from extracts of C. gilvus. After incubation for 1 h at 37 °C, the percentage conversion of cellobiose into glucose 1-phosphate was approx. 20%. The third step, the bioconversion of glucose 1-phosphate to α-glucose polymer, was carried out by α-glucan phosphory lase, incubated with primer at 37 °C for 24 h; about 55% conversion was obtained. The products formed white precipitates, gave a blue colour on treatment with iodine and were hydrolyzed by glucoamylase. This result shows that approx. 10% of cellulose could be converted to α-1.4-glucan, could be converted to α-1.4-glucan, such as amylose, via glucose 1-phosphate.