화학공학소재연구정보센터
Journal of Chemical Technology and Biotechnology, Vol.95, No.4, 1163-1172, 2020
The role of temperature, pH and nutrition in process development of the unique oleaginous yeast Metschnikowia pulcherrima
BACKGROUND Lipids produced from oleaginous yeasts are a promising alternative to terrestrial oils. Despite promising cellular yields of lipid however, an industrial process remains elusive. One key processing bottleneck is the need to provide nutrient-rich conditions for cellular growth and then extended nutrient-depleted conditions for lipid accumulation. Surprisingly, investigations detailing process development, particularly with a focus on kinetics, are rare in this field. RESULTS In this investigation we report on the unique oleaginous yeast Metschnikowia pulcherrima, where lipid accumulation >= 29.8% (w/w) was achieved without apparent nutrient limitation. The process was developed in stirred tank reactors through determining the influence of temperature, pH and nutrition on lipid production. A temperature of up to 25 degrees C and initial pH 5 could be applied to enhance initial reaction kinetics. Through the increased supply of yeast extract of up to 5% (w/w) of glucose, a maximum lipid production rate of 0.60 g L-1 h(-1) (4 h-average), productivity of 0.29 g L-1 h(-1), and yield of 0.17 g g(-1) glucose were achieved - the highest yet recorded with this yeast. Suitable to combat the excessive secretion of polyols of up to 0.11 g g(-1) glucose was an excess nutrient supply as well as a low cultivation temperature of 15 degrees C and moderate pH 5. CONCLUSIONS This study demonstrates that the lack of a starvation stage, coupled with effective process development is required for oleaginous yeasts to achieve the yields and productivities required for commercial lipid production. (c) 2019 Society of Chemical Industry