Exploring a novel GH13_5 α-amylase from Jeotgalibacillus malaysiensis D5T for raw starch hydrolysis

• Published in: AMB Express Vol. 14; no. 1; p. 71
• Main Authors: Radzlin, Nurfatini, Mohamad Ali, Mohd Shukuri, Goh, Kian Mau, Yaakop, Amira Suriaty, Zakaria, Iffah Izzati, Kahar, Ummirul Mukminin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 14.06.2024; Springer Nature B.V; SpringerOpen
• Subjects: Amylases; Biomedical and Life Sciences; Biotechnology; Calcium chloride; Caryophanaceae; Corn; Degradation; Enzymes; Glucans; Glycosidases; Glycoside hydrolase; Glycoside hydrolase family 13 subfamily 5; Hydrolysis; Jeotgalibacillus; Life Sciences; Maltose; Maltotetraose; Maltotriose; Marine bacteria; Microbial Genetics and Genomics; Microbiology; Mixtures; Optimization; Original; Original Article; Phylogeny; Potatoes; Raw starch hydrolysis; Rice; Saccharification; Starch; Starches; Sugar; Tapioca; Wheat; α-Amylase; α-Amylase; Raw starch hydrolysis; Glycoside hydrolase family 13 subfamily 5; Marine bacteria
• ISSN: 2191-0855; 2191-0855
• DOI: 10.1186/s13568-024-01722-3

α-Amylase plays a crucial role in the industrial degradation of starch. The genus Jeotgalibacillus of the underexplored marine bacteria family Caryophanaceae has not been investigated in terms of α-amylase production. Herein, we report the comprehensive analysis of an α-amylase (AmyJM) from Jeotgalibacillus malaysiensis D5 T (= DSM28777 T  = KCTC33550 T ). Protein phylogenetic analysis indicated that AmyJM belongs to glycoside hydrolase family 13 subfamily 5 (GH13_5) and exhibits low sequence identity with known α-amylases, with its closest counterpart being the GH13_5 α-amylase from Bacillus sp. KSM-K38 (51.05% identity). Purified AmyJM (molecular mass of 70 kDa) is stable at a pH range of 5.5–9.0 and optimally active at pH 7.5. The optimum temperature for AmyJM is 40 °C, where the enzyme is reasonably stable at this temperature. Similar to other α-amylases, the presence of CaCl 2 enhanced both the activity and stability of AmyJM. AmyJM exhibited activity toward raw and gelatinized forms of starches and related α-glucans, generating a mixture of reducing sugars, such as glucose, maltose, maltotriose, maltotetraose, and maltopentaose. In raw starch hydrolysis, AmyJM exhibited its highest efficiency (51.10% degradation) in hydrolyzing raw wheat starch after 3-h incubation at 40 °C. Under the same conditions, AmyJM also hydrolyzed tapioca, sago, potato, rice, and corn raw starches, yielding 16.01–30.05%. These findings highlight the potential of AmyJM as a biocatalyst for the saccharification of raw starches, particularly those derived from wheat. Key points A novel GH13_5 α-amylase (AmyJM) from Jeotgalibacillus malaysiensis D5 T was successfully expressed, purified, and biochemically characterized. AmyJM hydrolyzed raw starches from wheat, tapioca, sago, potato, rice, and corn at 40 °C, forming mixtures of reducing sugars. The properties of AmyJM suggest that the enzyme is potentially applicable in direct raw starch degradation processes.