Elevated, non-proliferative temperatures change the profile of fermentation products in Corynebacterium glutamicum
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APPLIED MICROBIAL AND CELL PHYSIOLOGY
Elevated, non-proliferative temperatures change the profile of fermentation products in Corynebacterium glutamicum Hikaru Mizuno 1 & Yota Tsuge 1,2 Received: 14 September 2020 / Revised: 9 November 2020 / Accepted: 16 November 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Although temperature is a crucial factor affecting enzymatic activity on biochemical and biofuel production, the reaction temperature for the generation of these products is usually set at the optimal growth temperature of the host strain, even under non-proliferative conditions. Given that the production of fermentation products only requires a fraction of the cell’s metabolic pathways, the optimal temperatures for microbial growth and the fermentative production of a target compound may be different. Here, we investigated the effect of temperature on lactic and succinic acids production, and related enzymatic activities, in wildtype and succinic acid-overproducing strains of Corynebacterium glutamicum. Interestingly, fermentative production of lactic acid increased with the temperature in wild-type: production was 69% higher at 42.5 °C, a temperature that exceeded the upper limit for growth, than that at the optimal growth temperature (30 °C). Conversely, succinic acid production was decreased by 13% under the same conditions in wild-type. The specific activity of phosphoenolpyruvate carboxylase decreased with the increase in temperature. In contrast, the other glycolytic and reductive TCA cycle enzymes demonstrated increased or constant activity as the temperature was increased. When using a succinic acid over-producing strain, succinic acid production was increased by 34% at 42.5 °C. Our findings demonstrate that the profile of fermentation products is dependent upon temperature, which could be caused by the modulation of enzymatic activities. Moreover, we report that elevated temperatures, exceeding the upper limit for cell growth, can be used to increase the production of target compounds in C. glutamicum. Key points • Lactate productivity was increased by temperature elevation. • Succinate productivity was increased by temperature elevation when lactate pathway was deleted. • Specific activity of phosphoenolpyruvate carboxylase was decreased by temperature elevation. Keywords Corynebacterium glutamicum . Glycolysis . TCA cycle . Lactic acid . Succinicacid . Temperature . Enzymaticactivity
Introduction Cell proliferation involves various biological processes, including synthesis of cellular building blocks, chromosome replication, and cell division, which individually requires multiple enzymatic reactions. The temperature is a crucial factor affecting the activity of enzymes, which is required for the * Yota Tsuge [email protected] 1
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
2
Institute for Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192
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