Microbial production of platform chemicals from glycerol

Forskningsoutput: KonferensbidragKonferensabstract

Abstract

The chemical industry is primarily dependent on fossil oil and gas as raw materials. With increasing demands on reducing the greenhouse gas emissions and carbon footprint attributed to fossil based production, the industry looks for alternative renewable cleaner resources to secure the supplies for future chemical and material products. The current trend in the shift to bio-based economy aims at using the residues and wastes from agricultural-, forest- and marine biomass and related industries as industrial feedstocks. In order to match the efficiency of the petrochemical industry, the biobased industry requires a set of platform chemicals from which a vast range of products can be derived. Organic acids and diols are among the important platform chemicals, many of which are found as intermediates or end products of metabolic pathways in several microbes.
In a project sponsored by the Swedish Governmental Agency for Innovation Systems at Lund University, glycerol obtained as a byproduct of biodiesel production, was used as a feedstock for the production of propionic acid (PA), 3-hydroxypropionaldehyde (3HPA), 3-hydroxypropionic acid (3HP) and 1,3-propanediol (1,3PDO), which are potential platforms for important chemicals like methacrylic acid, acrylic acid as well as polymers used in coatings, adhesives, automotive, construction, food, pharmaceuticals, and other industries. PA was produced using Propionibacterium acidipropionici cells. Different strategies for high cell density fermentations have been studied using immobilized cells, sequential batch fermentation and continuous fermentation with cell recycle, resulting in considerable enhancement in volumetric productivities. Heat-treated potato juice turned out to be an inexpensive and efficient nitrogen source for the fermentation.
Glycerol is used as an electron acceptor by Lactobacillus reuteri and is metabolized through propanediol-utilization (Pdu) pathway involving initial dehydration to 3HPA, which is subsequently oxidized into 3HP and simultaneously reduced into 1,3PDO. Production of 3HPA by the resting L. reuteri cells was possible by in situ removal of the inhibitory product. Flux analysis of the Pdu pathway was done to determine the optimal conditions for production of 3HPA, and co-production of 3HP and 1,3PDO by the cells. Furthermore, an integrated system for the conversion of glycerol to 3HP and then to acrylic acid was demonstrated.
The pdu pathway enzymes catalysing the oxidation of 3HPA were also expressed in Escherichia coli for the production of 3HP. Use of the resting cells led to the quantitative conversion of 3HPA to 3HP while the growing cells gave a mixture of 3HP and 1,3PDO due to the intrinsic 1,3-PD oxidoreductase activity of the E. coli cells. Copexpression of L. reuteri NADH oxidase allowed regeneration of NADH to allow continuous production of 3HP by the resting E. coli cells.

References
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Sabet-Azad R, Sardari RRR, Linares-Pastén JA, Hatti-Kaul R (2015) Bioresource Technology 180, 214-221

Detaljer

Författare
Enheter & grupper
Externa organisationer
  • LTH, Lund University
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Industriell bioteknik
Originalspråkengelska
StatusPublished - 2015
PublikationskategoriForskning
Peer review utfördJa
EvenemangNHBT-2015. New Horizons in Biotechnology - Trivandrum, Indien
Varaktighet: 2015 nov 222015 nov 25

Konferens

KonferensNHBT-2015. New Horizons in Biotechnology
LandIndien
OrtTrivandrum
Period2015/11/222015/11/25