Pyruvate stimulates transamination of leucine into α-ketoisocaproic acid and supports 3-methylbutanal production by Lactococcus lactis.

Autor:	Brandsma JB; dsm-firmenich, Taste, Texture & Health, Center for Food Innovation, Wageningen, 6708 WH, The Netherlands., Brinkman J; dsm-firmenich, Taste, Texture & Health, Center for Food Innovation, Wageningen, 6708 WH, The Netherlands., Wolkers-Rooijackers JCM; Wageningen University & Research, Food Microbiology, Wageningen, 6708 WG, The Netherlands., van Swam I; dsm-firmenich, Taste, Texture & Health, Center for Food Innovation, Wageningen, 6708 WH, The Netherlands., van Uitert K; dsm-firmenich, Taste, Texture & Health, Center for Food Innovation, Wageningen, 6708 WH, The Netherlands., Zwietering MH; Wageningen University & Research, Food Microbiology, Wageningen, 6708 WG, The Netherlands., Smid EJ; Wageningen University & Research, Food Microbiology, Wageningen, 6708 WG, The Netherlands.
Jazyk:	angličtina
Zdroj:	Journal of applied microbiology [J Appl Microbiol] 2024 Oct 03; Vol. 135 (10).
DOI:	10.1093/jambio/lxae257
Abstrakt:	Aim: To investigate the effect of pyruvate and glucose on leucine transamination and 3-methylbutanal production by Lactococcus lactis, including the comparison with cells possessing glutamate dehydrogenase (GDH) activity. Methods and Results: Lactococcus lactis cells were incubated in chemically defined medium (CDM) with the pH controlled at 5.2 to mimic cheese conditions. Pyruvate supplementation stimulated the production of the key flavour compound 3-methylbutanal by 3-4 times after 72 h of incubation. Concurrently, alanine production increased, demonstrating the involvement of pyruvate in transamination reactions. Glucose-metabolizing cells excreted α-ketoisocaproic acid and produced even 3 times more 3-methylbutanal after 24 h than pyruvate-supplemented cells. Conjugal transfer technique was used to transfer the plasmid pGdh442 carrying the gdh gene encoding for GDH to L. lactis. Introducing GDH did not stimulate the excretion of α-ketoisocaproic acid and the production of 3-methylbutanal. Conclusions: These results demonstrate that Lactococcus uses pyruvate to transaminate leucine into α-ketoisocaproic acid which supports 3-methylbutanal production. Surprisingly, GDH activity did not stimulate leucine transamination and 3-methylbutanal production. (© The Author(s) 2024. Published by Oxford University Press on behalf of Applied Microbiology International.)
Databáze:	MEDLINE
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