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Title (Primary) Three novel Clostridia isolates produce n-caproate and iso-butyrate from lactate: comparative genomics of chain-elongating bacteria
Author Liu, B.; Popp, D.; Müller, N.; Sträuber, H.; Harms, H.; Kleinsteuber, S.;
Journal Microorganisms
Year 2020
Department UMB;
Volume 8
Issue 12
Language englisch;
POF III (all) R31; T15;
Supplements https://www.mdpi.com/2076-2607/8/12/1970/s1
Keywords novel clostridial species; carboxylate platform; medium-chain carboxylates; branched-chain carboxylates; anaerobic fermentation; reverse β-oxidation
Abstract The platform chemicals n-caproate and iso-butyrate can be produced by anaerobic fermentation from agro-industrial residues in a process known as microbial chain elongation. Few lactate-consuming chain-elongating species have been isolated and knowledge on their shared genetic features is still limited. Recently we isolated three novel clostridial strains (BL-3, BL-4, and BL-6) that convert lactate to n-caproate and iso-butyrate. Here, we analyzed the genetic background of lactate-based chain elongation in these isolates and other chain-elongating species by comparative genomics. The three strains produced n-caproate, n-butyrate, iso-butyrate, and acetate from lactate, with the highest proportions of n-caproate (18%) for BL-6 and of iso-butyrate (23%) for BL-4 in batch cultivation at pH 5.5. They show high genomic heterogeneity and a relatively small core-genome size. The genomes contain highly conserved genes involved in lactate oxidation, reverse β-oxidation, hydrogen formation and either of two types of energy conservation systems (Rnf and Ech). Including genomes of another eleven experimentally validated chain-elongating strains, we found that the chain elongation-specific core-genome encodes the pathways for reverse β-oxidation, hydrogen formation and energy conservation, while displaying substantial genome heterogeneity. Metabolic features of these isolates are important for biotechnological applications in n-caproate and iso-butyrate production.
ID 23987
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=23987
Liu, B., Popp, D., Müller, N., Sträuber, H., Harms, H., Kleinsteuber, S. (2020):
Three novel Clostridia isolates produce n-caproate and iso-butyrate from lactate: comparative genomics of chain-elongating bacteria
Microorganisms 8 (12), art. 1970