Enhancing 3-hydroxypropionic acid production in combination with sugar supply engineering by cell surface-display and metabolic engineering of Schizosaccharomyces pombe.

Seiya Takayama,Yuuki Hirata,Takuya Matsumoto,Rie Konishi,Mayumi Kishida,Tsutomu Tanaka,Aiko Ozaki,Chisako Otomo,Akihiko Kondo

doi:10.1186/s12934-018-1025-5

Abstract

BackgroundEconomical production of value-added chemicals from renewable biomass is a promising path to sustainability. 3-Hydroxypropionic acid (3-HP) is an important chemical for building a bio-sustainable society. Establishment of 3-HP production from renewable resources such as glucose would provide a bio-sustainable alternative to the production of acrylic acid from fossil resources.ResultsHere, we describe metabolic engineering of the fission yeast Schizosaccharomyces pombe to enhance 3-HP production from glucose and cellobiose via the malonyl-CoA pathway. The mcr gene, encoding the malonyl-CoA reductase of Chloroflexus aurantiacus, was dissected into two functionally distinct fragments, and the activities of the encoded protein were balanced. To increase the cellular supply of malonyl-CoA and acetyl-CoA, we introduced genes encoding endogenous aldehyde dehydrogenase, acetyl-CoA synthase from Salmonella enterica, and endogenous pantothenate kinase. The resulting strain produced 3-HP at 1.0 g/L from a culture starting at a glucose concentration of 50 g/L. We also engineered the sugar supply by displaying beta-glucosidase (BGL) on the yeast cell surface. When grown on 50 g/L cellobiose, the beta-glucosidase-displaying strain consumed cellobiose efficiently and produced 3-HP at 3.5 g/L. Under fed-batch conditions starting from cellobiose, this strain produced 3-HP at up to 11.4 g/L, corresponding to a yield of 11.2% (g-3-HP/g-glucose; given that 1 g cellobiose corresponds to 1.1 g glucose upon digestion).ConclusionsIn this study, we constructed a series of S. pombe strains that produced 3-HP via the malonyl-CoA pathway. Our study also demonstrated that BGL display using cellobiose and/or cello-oligosaccharides as a carbon source has the potential to improve the titer and yield of malonyl-CoA- and acetyl-CoA-derived compounds.

Highlights

Economical production of value-added chemicals from renewable biomass is a promising path to sustainability. 3-Hydroxypropionic acid (3-HP) is an important chemical for building a bio-sustainable society
Reconstruction of a pathway for 3‐HP synthesis via malonyl‐CoA by coexpression of MCR‐C* and MCR‐N To develop a S. pombe strain capable of malonyl-CoAmediated production of 3-HP, we introduced two genes: C. aurantiacus mcr, which encodes malonyl-CoA reductase (MCR); and the endogenous acc gene, which encodes acetyl-CoA/biotin carboxylase
These results showed that providing cellobiose as the carbon source permits an on-going release of glucose by gradual degradation via the cell surface-displayed BGL, and cell surface display a b was effective for 3-HP production

Summary

Results

We describe metabolic engineering of the fission yeast Schizosaccharomyces pombe to enhance 3-HP production from glucose and cellobiose via the malonyl-CoA pathway. The mcr gene, encoding the malonyl-CoA reductase of Chloroflexus aurantiacus, was dissected into two functionally distinct fragments, and the activities of the encoded protein were balanced. The resulting strain produced 3-HP at 1.0 g/L from a culture starting at a glucose concentration of 50 g/L. We engineered the sugar supply by displaying beta-glucosidase (BGL) on the yeast cell surface. When grown on 50 g/L cellobiose, the beta-glucosidase-displaying strain consumed cellobiose efficiently and produced 3-HP at 3.5 g/L. Under fed-batch conditions starting from cellobiose, this strain produced 3-HP at up to 11.4 g/L, corresponding to a yield of 11.2% (g-3-HP/g-glucose; given that 1 g cellobiose corresponds to 1.1 g glucose upon digestion)

Conclusions

Results and discussion