Galactonic acid and its salts can be potentially used in foodstuffs and as specialty chemicals. So far, the researches on microbial conversion of galactose to galactonate are still scarce. In this study, we initially used Gluconobacter oxydans strain NL 71 to convert galactose to galactonic acid via aerobic fermentation by fed-batch and product separation process in shaken flasks, finally 390 g/L galactonic acid could be obtained after 96 h fermentation. To harvest calcium galactonate product, an aeration-agitation bioreactor with product drain port was applied. The lower solubility of calcium galactonate aided its crystallization during fermentation and after 96 h fermentation, approximately 720 g calcium galactonate crystals were produced from 1 L broth. The results showed that successive production of calcium galactonate by a combination of fed-batch and natural crystallization in the process of fermentation was feasible.

半乳糖酸及其盐可潜在地用于食品和特种化学品。迄今为止，关于半乳糖向半乳糖酸盐的微生物转化的研究仍然很少。在这项研究中，我们最初使用了氧化葡糖杆菌在摇瓶中通过补料分批和产物分离过程，通过好氧发酵将NL 71菌株半乳糖转化为半乳糖酸，发酵96 h后最终可得到390 g / L半乳糖酸。为了收获半乳糖酸钙产物，使用了带有产物排出口的曝气搅拌生物反应器。半乳糖酸钙的较低溶解度有助于其在发酵过程中的结晶，并且在96小时发酵后，从1 L肉汤中产生约720 g半乳糖酸钙晶体。结果表明，分批补料和自然结晶相结合在发酵过程中连续生产半乳糖酸钙是可行的。