固定化嗜热脂肪芽孢杆菌连续合成半乳糖寡糖的研究

利用固定了产β-半乳糖苷酶的嗜热脂肪芽孢杆菌，以乳糖为底物，在纤维床反应器中连续合成半乳糖寡糖(GOS)，最高得率为50.7%。在连续反应体系中，研究了底物浓度、pH、反应温度和停留时间对半乳糖寡糖合成的影响，确定最佳反应条件为底物浓度450 g/L、反应温度55℃、pH7.0、停留时间100 min。在连续反应24h后，流加1.5%的D-半乳糖能提高合成GOS的能力，固定化细胞反应体系中连续稳定操作120 h。

Study on Continuous Synthesis of Galacto-oligosaccharide by Immobilized Bacillus stearothermophilus

The galacto-oligosaccharide was synthesized continuously by immobilized Bacillus stearothermophilu producing beta-galactosidase in fibrous bed reactor. The effect of substrate concentration, pH, reaction temperature and retention time on production of GOS was investigated. The optimal reaction conditions were determined. Substrate concentration were 450 g/L; Reaction temperature was 55 degrees C; pH was 7.0; Residence time was 100 min. The product yield reached up to 50.7%. GOS synthesis was promoted by feeding 1.5% D-glactose after 24 h. The immobilized cell reactor can work stably for 120 h.