Open AccessImproved bioethanol production in an engineered K luyveromyces lactis strain shifted from respiratory to fermentative metabolism by deletion of NDI 1
Author(s) -
GonzálezSiso María Isabel,
Touriño Alba,
Vizoso Ángel,
PereiraRodríguez Ángel,
RodríguezBelmonte Esther,
Becerra Manuel,
Cerdán María Esperanza
Publication year - 2015
Publication title -
microbial biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.287
H-Index - 74
ISSN - 1751-7915
DOI - 10.1111/1751-7915.12160
Subject(s) - biochemistry , kluyveromyces lactis , biology , mutant , respiratory chain , mitochondrial matrix , mitochondrion , dehydrogenase , yeast , chemistry , cytosol , enzyme , saccharomyces cerevisiae , gene
Summary In this paper, we report the metabolic engineering of the respiratory yeast K luyveromyces lactis by construction and characterization of a null mutant ( Δ klndi 1) in the single gene encoding a mitochondrial alternative internal dehydrogenase. Isolated mitochondria of the Δ klndi 1 mutant show unaffected rate of oxidation of exogenous NADH , but no oxidation of matrix NADH ; this confirms that Kl Ndi1p is the only internal NADH dehydrogenase in K . lactis mitochondria. Permeabilized cells of the Δ klndi 1 mutant do not show oxidation of matrix NADH , which suggests that shuttle systems to transfer the NADH from mitochondrial matrix to cytosol, for being oxidized by external dehydrogenases, are not functional. The Δ klndi 1 mutation decreases the chronological life span in absence of nutrients. The expression of KlNDI 1 is increased by glutathione reductase depletion. The Δ klndi 1 mutation shifts the K . lactis metabolism from respiratory to fermentative: the Δ klndi 1 strain shows reduced respiration rate and increased ethanol production from glucose, while it does not grow in non‐fermentable carbon sources such as lactate. The biotechnological benefit of the Δ klndi 1 mutant for bioethanol production from waste cheese whey lactose was proved.