School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China; School of Medicine, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu, China.
College of Biosciences and Biotechnology, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110161, Liaoning, China.
Bioresour Technol. 2018 Jan;247:940-946. doi: 10.1016/j.biortech.2017.09.187. Epub 2017 Oct 3.
In the present study, a new strain of Lactobacillus brevis producing d-tagatose was isolated and identified. Then, the l-arabinose isomerase (L-AI) of this strain was displayed on the spore surface of Bacillus subtilis DB403 by using an anchoring protein CotG and a peptide linker (Gly-Gly-Gly-Gly-Ser). This displayed L-AI with high specific activity and stability was used as a novel immobilized biocatalyst for producing d-tagatose through batch and semi-continuous biotransformation. The conversion rate of d-tagatose from 125 g/L d-galactose was achieved 79.7% at 28 h, and the volumetric productivity reached 4.3 g/L/h at 20 h. Furthermore, the displayed L-AI showed a good performance on the reusability and remained 87% of the specific activity and 40.7% of the conversion rate after five recycles. A high efficient immobilized method for producing food-grade d-tagatose was established using spore surface-displayed L-AI.
在本研究中，分离并鉴定了一株产 d-塔格糖的短乳杆菌新菌株。然后，通过使用锚定蛋白 CotG 和肽接头（Gly-Gly-Gly-Gly-Ser），将该菌株的 l-阿拉伯糖异构酶（L-AI）展示在枯草芽孢杆菌 DB403 的孢子表面上。这种具有高比活性和稳定性的展示 L-AI 被用作一种新型固定化生物催化剂，通过分批和半连续生物转化生产 d-塔格糖。在 28 小时内，从 125 g/L d-半乳糖中获得了 79.7%的 d-塔格糖转化率，在 20 小时内达到了 4.3 g/L/h 的比生产率。此外，展示的 L-AI 在可重复使用性方面表现良好，在经过五次循环后，其比活性保持在 87%，转化率保持在 40.7%。使用孢子表面展示的 L-AI 建立了一种生产食品级 d-塔格糖的高效固定化方法。
