[en] Gluconic acid (GA) is a multifunctional organic acid with versatile applications in food, beverage and pharmaceutical industries. Recently, owing to increasing demand for cheaper gluconic acid and its salts; studies have mainly focused on more economical production process through using cheaper carbohydrate sources and isolation of appropriate microorganism. Despite progress towards its microbial production, fewer studies are available regarding its bacterial production at high temperature. It is believed that, withstanding high temperature during production of this acid can provide a new option for industrially cost effective production through reduction in cost of cooling.
Results: A major challenge associated with semi-continuous process of gluconate production using A. senegalensis was inability in glucose consumption during the late stationary phase and next fermentation cycles. Inactivation of respiration system (total dehydrogenases activity) and entrance of cells into viable but nonculturable (VBNC) state during stationary phase were the main reasons of this inability.
Conclusions: To improve gluconic acid fermentation at high temperature, it is necessary to induce the activity of total dehydrogenases as they carry the oxidation reaction of glucose. Supplementing the feed with ethanol, successfully conferred ability to cells for further glucose consumption.
