AmyZ1: a novel α-amylase from marine bacterium Pontibacillus sp. ZY with high activity toward raw starches

Abstract

Background Starch is an inexpensive and renewable raw material for numerous industrial applications. However, most starch-based products are not cost-efficient due to high-energy input needed in traditional enzymatic starch conversion processes. Therefore, α-amylase with high efficiency to directly hydrolyze high concentration raw starches at a relatively lower temperature will have a profound impact on the efficient application of starch. Results A novel raw starch digesting α-amylase (named AmyZ1) was screened and cloned from a deep-sea bacterium Pontibacillus sp. ZY. Phylogenetic analysis showed that AmyZ1 was a member of subfamily 5 of glycoside hydrolase family 13. When expressed in Escherichia coli , the recombinant AmyZ1 showed high activity at pH 6.0–7.5 and 25–50 °C. Its optimal pH and temperature were 7.0 and 35 °C, respectively. Similar to most α-amylases, AmyZ1 activity was enhanced (2.4-fold) by 1.0 mM Ca 2+ . Its half-life time at 35 °C was also extended from about 10 min to 100 min. In comparison, AmyZ1 showed a broad substrate specificity toward raw starches, including those derived from rice, corn, and wheat. The specific activity of AmyZ1 towards raw rice starch was 12,621 ± 196 U/mg, much higher than other reported raw starch hydrolases. When used in raw starch hydrolyzing process, AmyZ1 hydrolyzed 52%, 47% and 38% of 30% (w/v) rice, corn, and wheat starch after 4 h incubation. It can also hydrolyze marine raw starch derived from Chlorella pyrenoidosa , resulting in 50.9 mg/g DW (dry weight of the biomass) of reducing sugars after 4 h incubation at 35 °C. Furthermore, when hydrolyzing raw corn starch using the combination of AmyZ1 and commercial glucoamylase, the hydrolysis rate reached 75% after 4.5 h reaction, notably higher than that obtained in existing starch-processing industries. Conclusions As a novel raw starch-digesting α-amylase with high specific activity, AmyZ1 efficiently hydrolyzed raw starches derived from both terrestrial and marine environments at near ambient temperature, suggesting its application potential in starch-based industrial processes. Electronic supplementary material The online version of this article (10.1186/s13068-019-1432-9) contains supplementary material, which is available to authorized users.

Citraconylation and maleylation on the catalytic and thermodynamic properties of raw starch saccharifying amylase from Aspergillus carbonarius

“…Amylases are used in many bio-industrial processes and account for a sizeable fraction of the world's industrial enzyme market [ 1 ]. Amylases (alpha, beta and gluco-) catalyze the degradation of starch to simple sugars used as raw materials for a variety of products making them invaluable in the food and energy sector [ 2 ]. The heterogeneity of the starch molecule due to variations in granule morphology and organization results to its resistance to enzymic attack and incomplete hydrolysis.…”

Isolation, Screening and Time Course Study of Amylase-producing Fungi from Garri Processing Environment

“…Amylases (E.C.3.2.1.1) are used in many bioindustrial processes and account for a reasonable fraction of the world industrial enzyme markets (Singh et al, 2016). Amylases catalyse hydrolysis of starch to simple sugars used as raw materials for various products thereby making the enzymes essential in the food and energy sector (Okolo et al, 2000, Fang et al, 2019. Generally, amylases are grouped into α, γ, β subtypes.…”

A Novel Digestive α-Amylase from Blue Crab (Portunus segnis) Viscera: Purification, Biochemical Characterization and Application for the Improvement of Antioxidant Potential of Oat Flour

“…AmyZ1, an α-amylase from marine bacterium Pontibacillus sp. ZY, showed the highest activity at 35 °C and maintained more than 40% of its optimal activity at 20 °C, indicating the “cold-active” catalytic ability [ 38 ].…”

“…Similar behavior was reported by Fernandez et al [ 45 ] for α-amylase activity in five species of Mediterranean sparid fish, showing low stability at acid pH values. The pH stability of the digestive α-amylase BCA was higher than those of AmyZ1 which exhibited poor pH stability [ 38 ], amylase from the small abalone Haliotis sieboldii viscera (pH 6.0–8.0) [ 27 ] and tilapia intestinal amylase (pH 5.5–7.5) [ 32 ].…”

“…Unlike the α-amylase AmyZ1 of the marine bacterium Pontibacillus sp. ZY [ 38 ], the amylase SA-I from the small abalone Haliotis sieboldii [ 27 ], hard clam amylases AI-1, AI-2 and AII [ 26 ], BCA activity was slightly inhibited (7% of inhibition) by the chelating reagent EDTA, which could lead to the conclusion that the purified α-amylase from blue crab viscera is not a metalloenzyme. Fincan et al [ 49 ] reported the same behavior of the α-amylase from thermophilic Anoxybacillus flavithermus marine bacteria towards EDTA.…”