Optimization of fermentation conditions for production of <scp>l</scp>‐arabinose isomerase of <i>Lactobacillus plantarum</i> WU14

Abstract

Abstract As a substitute sweetener for sucrose, d ‐tagatose is widely used in products, such as health drinks, yogurt, fruit juices, baked goods, confectionery, and pharmaceutical preparations. In the fermentation process of l ‐AI produced by Lactobacillus plantarum, d ‐tagatose is produced through biotransformation and this study was based on the fermentation process of Lactobacillus plantarum WU14 producing l ‐AI to further research the biotransformation and separation process of d ‐tagatose. The kinetics of cell growth, substrate consumption, and l ‐arabinose isomerase formation were established by nonlinear fitting, and the fitting degrees were 0.996, 0.994, and 0.991, respectively, which could better reflect the change rule of d ‐tagatose biotransformation in the fermentation process of L. plantarum WU14. The separation process of d ‐tagatose was identified by decolorization, protein removal, desalination, and freeze drying, initially. Finally, the volume ratio of whole cell catalysts, d ‐galactose, and borate was 5:1:2 at 60°C, pH 7.17 through borate complexation; then, after 24 hr of conversion, the yield of d ‐tagatose was 58 g/L.