Multiple strategies to improve the yield of chitinase a from Bacillus licheniformis in Pichia pastoris to obtain plant g
- PDF / 1,432,980 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 64 Downloads / 174 Views
Microbial Cell Factories Open Access
RESEARCH
Multiple strategies to improve the yield of chitinase a from Bacillus licheniformis in Pichia pastoris to obtain plant growth enhancer and GlcNAc Wen Song, Nuo Zhang, Mo Yang, Yuling Zhou, Nisha He* and Guimin Zhang*
Abstract Chitinase and chitin-oligosaccaride can be used in multiple field, so it is important to develop a high-yield chitinase producing strain. Here, a recombinant Pichia pastoris with 4 copies of ChiA gene from Bacillus licheniformis and coexpression of molecular chaperon HAC1 was constructed. The amount of recombinant ChiA in the supernatant of high-cell-density fermentation reaches a maximum of 12.7 mg/mL, which is 24-fold higher than that reported in the previous study. The recombinant ChiA can hydrolyze 30% collodidal chitin with 74% conversion ratio, and GlcNAc is the most abundant hydrolysis product, followed by N, N′-diacetylchitobiose. Combined with BsNagZ, the hydrolysate of ChiA can be further transformed into GlcNAc with 88% conversion ratio. Additionally, the hydrolysate of ChiA can obviously accelerate the germination growth of rice and wheat, increasing the seedling height and root length by at least 1.6 folds within 10 days. Keywords: Chitinase, Pichia pastoris, Colloidal chitin, GlcNAc, Plant growth Introduction Chitin is the second abundant bioresource that is widely distributed in wastes from shellfish, krill processing, fungal fermentations and green alga. It is constituted of β(1 → 4)-linked N-acetyl-d-glucosamine (GlcNAc) units [1]. Chitin can be degraded by chitinases, which takes place in 2 steps, the initial cleavage of the chitin polymer by chitinases into chitin-oligosaccharide and further cleavage to GlcNAc by β-N-acetylglucosaminidase [2]. Chitin-oligosaccharide can promote plant growth and induce crops to produce disease resistance factors, effectively resist the infection of plant pathogens [3, 4]. GlcNAc can prevent bone and joint diseases, promote *Correspondence: [email protected]; [email protected]; [email protected]; [email protected] State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
wound healing, and be as antibacterial and anti-inflammatory agent [5, 6]. Therefore, it can be widely used in the industry of medicine, health care, food and cosmetics. At present, the chitin-oligosaccharide and GlcNAc are mainly prepared from chitin through chemical method, which cause severe environmental issues. Thus, using chitinases to hydrolyze chitin, with the mild reaction conditions and less pollution, has become a popular research direction. So, it is important to develop a highyield chitinase producing strain to lower the cost of chitin hydrolysis into GlcNAc and chitin-oligosaccharides. Bacillus licheniformis is a GRAS organism, has been used extensively in industry for the production of various enzymes and metabolites [7, 8]. Songsiriritthigul et al. firstly expressed the ChiA from B. licheniformis in Escherichia coli and characterize
Data Loading...
