Structural identification of alkyl glycosides obtained from the conversion of canna starch by immobilized α‐amylase from Aspergillus oryzae

Abstract

In this study, a novel route using immobilized a-amylase from Aspergillus oryzae as a catalyst for the preparation of alkyl glycosides (AGlys) from canna starch and methanol in water has been demonstrated. The effects of the experimental conditions on the conversion yield of AGlys were investigated. The optimized conditions were a canna starch concentration of 100 g/L, an enzyme concentration of 82.8 U/mL, and a reaction time of 24 h. A crude yield of 2.01% of AGlys was obtained under the optimal experimental conditions corresponding to an in-between situation of a donor-limiting and an acceptor-limiting regime. The products were then characterized by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The results showed that methyl-maltoside was the major product of the alcoholysis reaction.

Synthesis of alkyl glucosides catalyzed by immobilized α-amylase fromThermotoga maritima

“…Thus, incubation of the enzyme at high temperatures allows for the relaxation of regions that may have been restricted while immobilized, resulting in an increase in activity. This is also consistent with the increase in Topt commonly observed in other immobilized proteins (24, 26, 27).…”

“…Even though immobilization leads to a loss of activity, this is compensated by the possibility of reutilizing the enzyme during several reaction cycles. Strikingly, the immobilized enzyme retained above 50 % of alcoholysis activity after 5 reaction cycles (Figure 3), allowing the production of > 20 mg/mL of BG, in contrast to the previously reported 0.76-0.82 mg/mL titles obtained with Taka-amylase (22, 24). Although the amount of enzyme loaded does not affect the yield of BG during the first reaction cycle, loading higher amounts of protein maintains higher residual activity after several reaction cycles (Figure 3).…”

The Role of a Loop in the Non-catalytic Domain B on the Hydrolysis/Transglycosylation Specificity of the 4-α-Glucanotransferase from Thermotoga maritima

“…2 ). The nucleophilic acceptor could be a water molecule (hydrolysis), or a molecule different from water (transglycosylation), such as another sugar, an alcohol [ 22 , 23 ], a phenol [ 24 ], a carboxylic acid [ 4 ] or even an amine [ 25 ]. Usually, transglycosylation shows lower rates than hydrolysis in members of GH13.…”