An optimized cocktail of chitinolytic enzymes to produce N,N'-diacetylchitobiose and N-acetyl-d-glucosamine from defatted krill by-products

  • Int J Biol Macromol. 2019 Jul 15;133:1029-1034. doi: 10.1016/j.ijbiomac.2019.04.114.
Fangmeng Chu  1 ,  Di Wang  1 ,  Tian Liu  2 ,  Hongyu Han  1 ,  Yike Yu  3 ,  Qing Yang  4
Affiliations
  • 1. State Key Laboratory of Fine Chemical Engineering and School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China.
  • 2. State Key Laboratory of Fine Chemical Engineering and School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China. Electronic address: [email protected].
  • 3. Liaoyu Group Co., Ltd., Dalian 116113, China.
  • 4. State Key Laboratory of Fine Chemical Engineering and School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China; Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China. Electronic address: [email protected].
PMID: 31004644 DOI: 10.1016/j.ijbiomac.2019.04.114
Abstract

Defatted krill powder (DKP), the byproduct of krill oil industry, is a resource of biological macromolecules. Here, one Bacterial protease, three Bacterial chitinases and one insect N-acetyl-d-hexosaminidase were integratively used to produce peptide, N,N'-diacetylchitobiose [(GlcNAc)2] and N-acetyl-d-glucosamine (GlcNAc) from DKP. First, alkaline protease was found to outperform neutral protease in deproteinizing DKP and the resultant krill peptides were rich in essential Amino acids (41.4%). Second, the mutant of chitinase A from Serratia marcescens [SmChiA-F232W/F396W (SmChiA-M)] was found to be 32% faster than wild-type SmChiA in hydrolyzing the deproteinized DKP (DDKP) and showed significant synergy with chitinase B from S. marcescens (SmChiB) and chitinase C from S. marcescens (SmChiC). Then two SmChiA-M-based enzyme combinations [SmChiA-M + SmChiB + SmChiC and SmChiA-M + SmChiB + SmChiC + OfHex1 (an insect N-acetyl-d-hexosaminidase from Ostrinia furnacalis)] were designed to produce (GlcNAc)2 and GlcNAc, respectively, from DDKP. A yield of 2.04 g/L (GlcNAc)2 or 2.71 g/L GlcNAc (each with 95% purity) could be obtained from 20 g/L DDKP in 24 h.

Keywords
Antarctic krill; Chitin; Chitinase; N-acetyl-d-glucosamine; Protease.
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