Novel α-amylases Amy A1 and Amy A2 from digestive tract of tropical house cricket Gryllodes sigillatus (Orthoptera: Gryllidae): hydrolysis and transglycosylation reactions.

The aim of the study was to investigate the ability of Amy A1 and Amy A2 α-amylases from digestive tract of the tropical house cricket Gryllodes sigillatus to hydrolyse the gelatinized starches of some tropical crops and their potentiality to catalyze tranglycosylation reactions. The Amy A1 and Amy A2 α-amylases hydrolyzed efficiently the starches from tubers (yam, cocoyam) and roots (cassava) to obtain reducing sugars content ranging from 22.2 μg to 62.1 μg after 6 hours incubation. However, the both α-amylases hydrolyzed less the starches from cereal (maize, millet). Otherwise, they catalyzed the transglycosylation reactions with soluble starch as donor and phenol as acceptor. The optimisation of the transfer product yield was studied as functions of pH, incubation time, concentration of donor and acceptor. Indeed, the obtained yield in experimental optimum conditions were 63.1 ± 0.27 % and 51.6 ± 0.03 % for Amy A1 and Amy A2 α-amylases respectively. On the basis of these results, α-amylases from the digestive tract of the cricket G. sigillatus appear to be a valuable tool for the glycosylation of phenolic compounds.