Amylomaltase fromThermus filiformis: expression inSaccharomyces cerevisiaeand its use in starch modification

Abstract

Aim: To express amylomaltase from Thermus filiformis (TfAM) in a generally recognized as safe (GRAS) organism and to use the enzyme in starch modification. Methods and Results: TfAM was expressed in Saccharomyces cerevisiae, using 2% (w/v) galactose inducer under GAL1 promoter. The enzyme was thermostable with high disproportionation and cyclization activities. The main large-ring cyclodextrin (CD) products were CD24-CD29, with CD26 as maximum at all incubation times. TfAM was used to modify cassava and pea starches, the amylose content decreased 18% and 30%, respectively, when 5% (w/v) starch was treated with 0Á5 U TfAM g À1 starch. The increase in short branched chain (DP, degree of polymerization, 1-5) and the broader chain length distribution pattern which extended to the longer chain (DP40) after TfAM treatment were observed. The thermal property was changed, with an increase in retrogradation of starch as suggested by a lower enthalpy. Conclusions: TfAM was successfully expressed in S. cerevisiae and was used to make starches with new functionality. Significance and Impact of the Study: This is the first report on the expression of AM in the GRAS yeast and the production of a modified starch gel from pea starch to improve the versatility of starch for food use.

Clean label starch: production, physicochemical characteristics, and industrial applications

“…4aGTase also known as amylomaltase and D-enzyme (disproportionationg enzyme), catalyses transglycosylation reaction on the starch substrate through disproportionation, cyclization, coupling and hydrolysis reactions (Takaha et al, 1996). This enzyme can produce a modified amylopectin clusters and cyclic products of a-1,4-glucan called cycloamyloses or large-ring cyclodextrins by inter and intramolecular transglycosylation (Nimpiboon et al, 2020). It is also possible to manufacture thermoreversible starch gel using this enzyme (Kaper et al, 2005;.…”

Production of Large-Ring Cyclodextrins by Amylomaltases

“…On the contrary, CgAM demonstrated larger LR-CDs (CD31) at shorter incubation time at 30 min, while the LR-CDs became smaller at 4 and 24 h incubation time where the principal products were CD27-28 and CD25, respectively [36]. On the other hand, the amounts of LR-CDs were observed to be increased along with longer incubation time [67].…”

Amylomaltases in Extremophilic Microorganisms

“…Amylomaltases have been therefore employed to produce thermoreversible gels to be used as alternatives to animal gelatin. Enzymes from P. aerophilum [ 11 ], P. calidifontis [ 13 ], T. uzoniensis [ 14 ], T. aquaticus [ 18 ], and T. filiformis [ 22 ] have been assayed for the production of thermoreversible starch gels from different sources (potato, tapioca, corn, rice, cassava, pea), with slightly different properties related to the substrates and relative amylose and amylopectin differential compositions.…”

“…In light of the possible applications in the food industry, extreme amylomaltases were also produced using GRAS (Generally Recognized as Safe) organisms, such as B. subtilis and Saccharomyces , as in the cases of enzymes from T. aquaticus [ 41 ], T. thermophilus [ 24 ] and T. filiformis [ 22 ].…”