TITLE:
The Study of Food-Grade Induced Expression and Enzymatic Properties of L-Arabinose Isomerase from Lactobacillus plantarum WU14 with High D-Tagatose Yield
AUTHORS:
Xiaoyu Chang, Bi Ying, Yanli Zhang, Huifang Cao, Tong Zhou, Ping’an Zhong, Bo Xu
KEYWORDS:
D-Tagatose, Lactobacillus plantarum WU14, L-Arabinose Isomerase, Recombinant PCR Technology, Food-Grade Expression
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.7 No.4,
April
28,
2016
ABSTRACT: L-arabinose isomerase (L-AI) is the key enzyme for D-galactose isomerization of D-tagatose by biological
method. In this research, Lactobacillus plantarum WU14 with high D-tagatose yield was
identified as Lactobacillus plantarum was isolated from the number of lactic acid bacteria from
pickled vegetables. The crude L-arabinose isomerase activity of Lactobacillus plantarum WU14
with high D-tagatose yield was 13.95 U/mL under the optimal temperature 60°C, pH 7.17 and substrate
concentration 0.8 mol/L, and the conversion rate of 56.12% could be gained after 28 hours.
Protein structure and specific of L-Arabinose Isomerase of Lactobacillus plantarum WU14 were
researched. The results showed that L-arabinose isomerase is mainly composed of alpha helix and
random coil. Then the recombinant L-AI gene was inserted into the food-grade expression vector
pRNA48 and expressed in L. lactis NZ9000 successfully. The target protein expression reached the
maximum amount when the induced concentration of nisin reaches 30 ng/mL after 12 h. And the
crude enzyme activity of recombinant bacteria reached 6.21 U/mL under 60°C. Otherwise the optimal
conversion rate recombinant of L. lactis NZ9000/pRNA48-L-AI can reach 39.21% under the
temperature of 50°C, pH 7.17 and D-galactose concentration was 0.6 mol/L.