Two-Stage Sequential Continuous Enzymatic Hydrolysis of Cassava Starch Through In-Line Static Mixer Reactor

Abstract

A state-of-the-art process with two In-Line Static Mixer Reactor (ISMR) was invented for two-stage sequential continuous enzymatic hydrolyses of cassava starch. Starch was liquefied and then subsequently saccharified continuously and efficiently through the two units of ISMR. They comprised two major static dynamic mixers connected, each 0.01 m in diameter and 12.6 m in length, one for liquefaction and one for saccharification. Starch at concentrations of 40% (w/v) and 45% (w/v) was continuously liquefied by α-amylase at 95 oC and pH 6.5 through the first unit of ISMR at feed rates of 15 and 30 mL/min, and simultaneously dextrin solution from liquefaction was also continuously saccharified by glucoamylase at 65 oC and pH 4.5 through the ISMR second unit at flow rates of 30 or 60 mL/min. The highest reducing sugar concentration of 178.86 mg/mL with an DE of 99.29 was obtained from hydrolyses of 45% (w/v) starch at a feed rate of 15 mL/min for saccharification because it possessed the longest residence reaction time for both processes of 131.88 min. The liquefaction and subsequent saccharification have been done continuously and efficiently within ~2 h. It look at least ~23-25 h shorter time when compared to a conventional hydrolysis method using a stirred tank reactor. This two-stage sequential ISMR essentially showed an excellent performance with scaleable potential for the commercial production of sugars from continuous starch hydrolyses instead of batch operation.