Bioconversion of starches into maltotetraose using Pseudomonas stutzeri maltotetraohydrolase in a membrane recycle bioreactor: Effect of multiple enzyme systems and mass balance study

摘要: Abstract A simplified single-step method involving simultaneous production and purification of maltotetraose (G 4 ) by employing ultrafiltration (UF) membranes was previously proposed. The addition a pretreatment step using pullulanase then the G -amylase expected to increase yield . single-enzyme system, however, showed 0.42 g higher total product output than successive dual-enzyme system throughout 6 h reaction. could be improved after removing unwanted side with UF. Experiments were conducted larger pore size, but this did not significantly output. membrane unit molecular weight cutoff 1,000 most appropriate size for -exo-α-amylase recycle bioreactor system. amount substrate fouled in during 6-h reaction estimated as 69 mg glucose equivalent when concentration 0.25% (w/v). mass balance equation indicated that percent conversion soluble starch at steady state 65%.