Lactic acid bacteria (LAB) are among the most interesting organisms for industrial processes with a long history of application as food starters and biocontrol agents, and an underexploited potential for biorefineries converting biomass into high-value compounds. Lactic acid (LA), their main fermentation product, is among the most requested chemicals owing to its broad range of applications. Notably, LA polymers, i.e., polylactides, have high potential as biodegradable substitutes of fossil-derived plastics. However, LA production by LAB fermentation is currently too expensive for polylactide to be cost-competitive with traditional plastics. LAB have complex nutritional requirements and cannot ferment inexpensive substrates such as cellulose. Metabolic engineering could help reduce such nutritional requirements and enable LAB to directly ferment low-cost polysaccharides. Here, we engineered a Lactococcus lactis strain which constitutively secretes a β-glucosidase and an endoglucanase. The recombinant strain can grow on cellooligosaccharides up to at least cellooctaose and efficiently metabolizes them to L-LA in single-step fermentation. This is the first report of a LAB able to directly metabolize cellooligosaccharides longer that cellohexaose and a significant step towards cost-sustainable consolidated bioprocessing of cellulose into optically pure LA

Recombinant Lactococcus lactis for efficient conversion of cellodextrins into L-lactic acid

GANDINI, Chiara;TARRARAN, LOREDANA;KALEMASI, DENIS;PESSIONE, Enrica;MAZZOLI, Roberto
Last
2017-01-01

Abstract

Lactic acid bacteria (LAB) are among the most interesting organisms for industrial processes with a long history of application as food starters and biocontrol agents, and an underexploited potential for biorefineries converting biomass into high-value compounds. Lactic acid (LA), their main fermentation product, is among the most requested chemicals owing to its broad range of applications. Notably, LA polymers, i.e., polylactides, have high potential as biodegradable substitutes of fossil-derived plastics. However, LA production by LAB fermentation is currently too expensive for polylactide to be cost-competitive with traditional plastics. LAB have complex nutritional requirements and cannot ferment inexpensive substrates such as cellulose. Metabolic engineering could help reduce such nutritional requirements and enable LAB to directly ferment low-cost polysaccharides. Here, we engineered a Lactococcus lactis strain which constitutively secretes a β-glucosidase and an endoglucanase. The recombinant strain can grow on cellooligosaccharides up to at least cellooctaose and efficiently metabolizes them to L-LA in single-step fermentation. This is the first report of a LAB able to directly metabolize cellooligosaccharides longer that cellohexaose and a significant step towards cost-sustainable consolidated bioprocessing of cellulose into optically pure LA
2017
114
12
2807
2817
http://onlinelibrary.wiley.com/doi/10.1002/bit.26400/full
Polylactide, metabolic engineering, recombinant cellulolytic strategy, cellulase, beta-glycosidase
Gandini, Chiara; Tarraran, Loredana; Kalemasi, Denis; Pessione, Enrica; Mazzoli, Roberto
File in questo prodotto:
File Dimensione Formato  
4aperto_Gandini et al. 2017 pre-print x IRIS.pdf

Accesso aperto

Tipo di file: PREPRINT (PRIMA BOZZA)
Dimensione 2.04 MB
Formato Adobe PDF
2.04 MB Adobe PDF Visualizza/Apri
bit.26400.pdf

Accesso riservato

Tipo di file: PDF EDITORIALE
Dimensione 1.63 MB
Formato Adobe PDF
1.63 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1647445
Citazioni
  • ???jsp.display-item.citation.pmc??? 2
  • Scopus 16
  • ???jsp.display-item.citation.isi??? 15
social impact