Harnessing originally robust yeast for rapid lactic acid bioproduction without detoxification and neutralization

• Published in: Scientific reports Vol. 12; no. 1; p. 13645
• Main Authors: Pangestu, Radityo, Kahar, Prihardi, Kholida, Lutfi Nia, Perwitasari, Urip, Thontowi, Ahmad, Fahrurrozi, Lisdiyanti, Puspita, Yopi, Ogino, Chiaki, Prasetya, Bambang, Kondo, Akihiko
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11-08-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 631/326; 631/61; 631/61/252; 631/61/318; Acids; Bagasse; Cell density; Cultivation; Detoxification; Ethanol; Fermentation; Humanities and Social Sciences; Hydrolysates; Industrial strains; Lactic acid; LDH gene; Lignocellulose; multidisciplinary; Neutralization; Performance assessment; Science; Science (multidisciplinary); Sugarcane; Yeasts
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-17737-4

Acidic and chemical inhibitor stresses undermine efficient lactic acid bioproduction from lignocellulosic feedstock. Requisite coping treatments, such as detoxification and neutralizing agent supplementation, can be eliminated if a strong microbial host is employed in the process. Here, we exploited an originally robust yeast,
Saccharomyces cerevisiae
BTCC3, as a production platform for lactic acid. This wild-type strain exhibited a rapid cell growth in the presence of various chemical inhibitors compared to laboratory and industrial strains, namely BY4741 and Ethanol-red. Pathway engineering was performed on the strain by introducing an exogenous
LDH
gene after disrupting the
PDC1
and
PDC5
genes. Facilitated by this engineered strain, high cell density cultivation could generate lactic acid with productivity at 4.80 and 3.68 g L
−1
 h
−1
under semi-neutralized and non-neutralized conditions, respectively. Those values were relatively higher compared to other studies. Cultivation using real lignocellulosic hydrolysate was conducted to assess the performance of this engineered strain. Non-neutralized fermentation using non-detoxified hydrolysate from sugarcane bagasse as a medium could produce lactic acid at 1.69 g L
−1
 h
−1
, which was competitive to the results from other reports that still included detoxification and neutralization steps in their experiments. This strategy could make the overall lactic acid bioproduction process simpler, greener, and more cost-efficient.