Selectivity in citric acid production by Yarrowia lipolytica

This experimental study reports about production selectivity in the ferment ation of glucose to citric acid by Yarrowia lipolytica as a function of sub strate concentration. Batch runs featuring biomass growth and one or two ci tric acid production phases were carried out in a 15-1 stirred tank ferment er. The presented results demonstrate that working at high initial substrat e concentration in the production phase is beneficial both in terms of a hi gher production rate of citric acid, the desired metabolite (reaching 0.077 h(-1)) and of a higher utilization degree of the employed carbon source (y ield up to 0.384 g(c.a)/g(glucose)). The production rate of isocitric acid, the major undesired metabolite, was found to be practically constant over the tested initial substrate concentration range. (C) 2001 Elsevier Science Inc. All rights reserved.