Enhancing l-malate production of Aspergillus oryzae FMME218-37 by improving inorganic nitrogen utilization
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Microbial l-malate production from renewable feedstock is a promising alternative to petroleum-based chemical synthesis. However, high l-malate production of Aspergillus oryzae was achieved to date using organic nitrogen, with inorganic nitrogen still unable to meet industrial applications. In the current study, we constructed a screening system and nitrogen supply strategy to improve l-malate production with ammonium sulphate [(NH4)2SO4] as the sole nitrogen source. First, we generated and identified a high-producing mutant FMME218-37, which stably boosted l-malate production from 30.73 to 78.12 g/L, using a combined screening system with morphological characteristics. Then, by analyzing the fermentation parameters and physiological characteristics, we further speculated the key factor was the unbalance of carbon and nitrogen absorption. Finally, the titer and productivity of l-malate was increased to 95.2 g/L and 0.57 g/(L h) by regulating the nitrogen supply module to balance carbon and nitrogen absorption, which represented the highest level in A. oryzae with (NH4)2SO4 as nitrogen source achieved to date. Moreover, our findings using a low-cost substrate may lead to building an economical cell factory of A. oryzae for l-malate production.
Keywordsl-Malate Aspergillus oryzae (NH4)2SO4 Screening system Nitrogen supply module Carbon and nitrogen absorption
This work was funded by the National Natural Science Foundation of China (21676118, 21706095).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
- Kusnan MB, Berger MG, Fock HP (1987) The involvement of glutamine synthetase/glutamate synthase in ammonia assimilation by Aspergillus nidulans. J Gen Appl Microbiol 133(5):1235–1242Google Scholar
- Marzluf GA (1997) Genetic regulation of nitrogen metabolism in the fungi. Mol Microbiol 61(1):17–32Google Scholar
- Werpy TA, Holladay JE, White JF (2004) Top value added chemicals from biomass: I. Results of Screening for Potential Candidates from Sugars and Synthesis Gas. Synthetic FuelsGoogle Scholar
- Zelle RM, de Hulster E, van Winden WA, de Waard P, Dijkema C, Winkler AA, Geertman JMA, van Dijken JP, Pronk JT, van Maris AJA (2008) Malic acid production by Saccharomyces cerevisiae: engineering of pyruvate carboxylation, oxaloacetate reduction, and malate export. Appl Environ Microb 74(9):2766–2777CrossRefGoogle Scholar
- Zhe C, Wang ZP, Wang GY, Khan I, Chi ZM (2014) Microbial biosynthesis and secretion of l-malic acid and its applications. Crit Rev Biotechnol 36(1):99–107Google Scholar