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Alcoholysis reactions from starch with α‐amylases
Author(s) -
Santamaría R.I,
Del Río G,
Saab G,
Rodríguez M.E,
Soberón X,
López-Munguía A
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00667-5
Subject(s) - starch , hydrolysis , methanol , chemistry , amylase , bacillus licheniformis , aspergillus oryzae , substrate (aquarium) , organic chemistry , aspergillus niger , context (archaeology) , enzyme , chromatography , biochemistry , bacteria , bacillus subtilis , biology , ecology , paleontology , genetics
The ability of α‐amylases from different sources to carry out reactions of alcoholysis was studied using methanol as substrate. It was found that while the enzymes from Aspergillus niger and Aspergillus oryzae , two well‐studied saccharifying amylases, are capable of alcoholysis reactions, the classical bacterial liquefying α‐amylases from Bacillus licheniformis and Bacillus stearothermophilus are not. The effect of starch and methanol concentration, temperature and pH on the synthesis of glucosides with α‐amylase from A. niger was studied. Although methanol may inactivate α‐amylase, a 90% substrate relative conversion can be obtained in 20% methanol at a high starch concentration (15% w/v) due to a stabilizing effect of starch on the enzyme. As the products of alcoholysis are a series of methyl‐oligosaccharides, from methyl‐glucoside to methyl‐hexomaltoside, alcoholysis was indirectly quantified by high performance liquid chromatography analysis of the total methyl‐glucoside produced after the addition of glucoamylase to the α‐amylase reaction products. More alcoholysis was obtained from intact soluble starch than with maltodextrins or pre‐hydrolyzed starch. The biotechnological implications of using starch as substrate for the production of alkyl‐glucosides is analyzed in the context of these results.