Metabolic engineering of Rhizopus oryzae for the production of platform chemicals

Bas J Meussen,Johan P M Sanders,Leo H De Graaff,Ruud A Weusthuis

doi:10.1007/s00253-012-4033-0

Bas J Meussen, Johan P M Sanders + Show 2 more

Open Access

https://doi.org/10.1007/s00253-012-4033-0

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Abstract

Rhizopus oryzae is a filamentous fungus belonging to the Zygomycetes. It is among others known for its ability to produce the sustainable platform chemicals l-(+)-lactic acid, fumaric acid, and ethanol. During glycolysis, all fermentable carbon sources are metabolized to pyruvate and subsequently distributed over the pathways leading to the formation of these products. These platform chemicals are produced in high yields on a wide range of carbon sources. The yields are in excess of 85 % of the theoretical yield for l-(+)-lactic acid and ethanol and over 65 % for fumaric acid. The study and optimization of the metabolic pathways involved in the production of these compounds requires well-developed metabolic engineering tools and knowledge of the genetic makeup of this organism. This review focuses on the current metabolic engineering techniques available for R. oryzae and their application on the metabolic pathways of the main fermentation products.

Highlights

Fossil resources such as coal, oil, and gas are estimated to become exhausted or unattractive to mine for bulk use within the coming decades
With the ever-growing demand for platform chemicals, the increased costs of raw materials, and sustainability requirements, efficient biocatalysts are required. One of these biocatalysts is formed by the filamentous fungus R. oryzae
This organism is able to produce ethanol, L-(+)-lactic acid, and fumaric acid, and the ability to produce fumaric acid is what sets this genera apart from other fungi. These platform chemicals are produced in high yield on a wide range of carbon sources, in excess of 85 % of the theoretical yield for L-(+)-lactic acid and ethanol and 65 % for fumaric acid

Summary

Introduction

Fossil resources such as coal, oil, and gas are estimated to become exhausted or unattractive to mine for bulk use within the coming decades. Ward et al (1936) described the production of L-(+)-lactic acid from glucose by R. oryzae strains, culminating to a yield of 0.62 g/g. The LDHB-encoding gene was expressed on non-fermentable carbon sources such as ethanol, glycerol, and lactate (Skory 2000).

Results

Conclusion