Yin Lei

Publications (3)8.9 Total impact

• Article: Preferential and rapid degradation of raw rice starch by an α-amylase of glycoside hydrolase subfamily GH13_37.

  Yin Lei, Hui Peng, Ying Wang, Yuantao Liu, Fang Han, Yazhong Xiao, Yi Gao
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  ABSTRACT: The α-amylase (AmyP) from a marine metagenomic library belongs to the recently classified glycoside hydrolase subfamily GH13_37. The degradation abilities of AmyP on a broad range of raw starch granules were examined at 40 °C and pH 7.5. It was found that AmyP is a raw starch-degrading enzyme, exhibiting a unique and remarkable ability to preferentially and very rapidly digest raw rice starch. The specific activity of raw rice starch was reached 118.5 ± 0.6 Umg(-1), which was much higher than that of other raw starches. The final hydrolysis degrees were obtained in 4 h for 1 % raw rice starch and 1 h for 8 % concentration, indicating a very rapid speed of hydrolysis. The presence of a starch residue resistant was the main limiting factor for complete hydrolysis, although end product inhibition also existed, especially at high starch concentrations. AmyP randomly attacks unique or susceptible sites on raw rice starch granules, and releases glucose, maltose, and maltotriose as end products. This is the first biochemical characterization of the raw starch-degrading ability of an α-amylase of family GH13_37. The specific ability towards raw rice starch has never been described before, and this makes AmyP a promising candidate for use as a novel enzyme in rice starch processing.
  Applied Microbiology and Biotechnology 05/2012; 94(6):1577-84. · 3.42 Impact Factor
• Article: Identification and phylogenetic characterization of a new subfamily of α-amylase enzymes from marine microorganisms.

  Yang Liu, Yin Lei, Xuecheng Zhang, Yi Gao, Yazhong Xiao, Hui Peng
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  ABSTRACT: A gene encoding a starch-hydrolyzing enzyme was isolated from a marine metagenomic library and overexpressed in Escherichia coli. The enzyme, designated AmyP, shows very low similarity to full-length sequences of known α-amylases, although a catalytic domain correlated with the α-amylase superfamily was identified. Based on the range of substrate hydrolysis and the product profile, the protein was clearly defined as a saccharifying-type α-amylase. Sequence comparison indicated that AmyP was related to four putative glycosidases previously identified only in bacterial genome sequences. They were all from marine bacteria and formed a new subfamily of glycoside hydrolase GH13. Moreover, this subfamily was closely related to the probable genuine bacterial α-amylases (GH13_19). The results suggested that the subfamily may be an independent clade of ancestral marine bacterial α-amylases.
  Marine Biotechnology 11/2011; 14(3):253-60. · 3.43 Impact Factor
• Article: A new subspecies of Anoxybacillus flavithermus ssp. yunnanensis ssp. nov. with very high ethanol tolerance.

  Jun Dai, Yang Liu, Yin Lei, Yi Gao, Fang Han, Yazhong Xiao, Hui Peng
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  ABSTRACT: In a search for thermophilic ethanol-tolerant bacteria, water-sediment samples collected at springs in Yunnan province of China were screened by ethanol enrichment. A novel thermophilic bacterium, strain E13(T) , was isolated. It exhibits a unique and remarkable ability to preferably grow in the presence of ethanol and is able to tolerate 13% (v/v) ethanol at 60 °C. The isolate is a facultative aerobic, Gram-positive, motile, spore-forming rod that is capable of utilizing a range of carbon sources, such as xylose, arabinose and cellobiose. Phylogenetic analysis based on 16S rRNA gene similarity showed the strain to be affiliated with the species Anoxybacillus flavithermus (99.2% sequence similarity). DNA-DNA hybridization comparisons demonstrated a 64.8% DNA-DNA relatedness between strain E13(T) and A. flavithermus DSM 2641(T) . On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA hybridization data, it was concluded that the isolate merited classification as a novel subspecies of A. flavithermus, for which the name Anoxybacillus flavithermus ssp. yunnanensis ssp. nov. is proposed. The type strain of this subspecies is E13(T) (=CCTCC AB2010187(T) =KCTC 13759(T) ).
  FEMS Microbiology Letters 07/2011; 320(1):72-8. · 2.04 Impact Factor