European Research Project Searching for More Efficient and Cost-Effective Enzymes for Cellulosic Biofuel Production
|Scope of the DISCO project. Click to enlarge.|
The EU-funded project known as DISCO (Discovery of Novel Enzymes & Reaction Mechanisms for Lignocellulose Hydrolysis), is halfway through its four-year quest to develop more efficient and cost-effective enzyme tools from microorganisms to produce bioethanol from lignocellulosic biomass waste—such as spruce chips from paper-making, wheat straw from farming and waste bran from milling—and to understand how these enzymes work.
The overall aim of the project is to end up with a cocktail of microorganism-derived enzymes that can simultaneously breakdown the complex lignocellulose into simple sugars, and enable yeast co-fermentation to produce bioethanol (simultaneous saccharification and fermentation, SSF).
The most promising enzymes will be tested in a pilot scheme using the most relevant European material, softwood and wheat straw. As well as enzyme discovery, the project will look to better understand the enzyme reactions and what limits their rate.
The DISCO project is subdivided into five Work Packages:
WP1. Choice and evaluation of lignocellulosic matrices
The most suitable lignocellulosic materials, and the most appropriate pre-treatments needed to prepare them for enzyme degradation will be identified. The chemical, polymeric and anatomical structure will be characterized and assayed during enzyme degradation. Recalcitrant material will be further analysed to discover the basis of its resistance.
WP2. Enzyme screening
Screening for novel enzymes will use relevant culture collections, enriched soil samples and enzyme collections to find enzymes able to degrade selected materials. Genome mining and metagenomic libraries will also be screened. The characteristics of most promising enzymes will be characterized.
WP3. Protein production
Candidate enzymes from screening and genome mining will be produced and purified. Gene sequences encoding the most interesting cellulases and hemicellulases will be isolated, cloned and expressed in fungal expression hosts.
WP4. Mode of action and synergy of cellulose and xylan degrading enzymes
The precise mechanism of action and preferred substrates of novel enzymes will be studied, and their activity to work synergistically with xylanolytic enzymes assessed. The process of lignocellulose hydrolysis will be studied to identify bottlenecks in the system that limit the overall rate.
WP5. Evaluation of the novel enzymes in saccharification and fermentation
Enzymes will be evaluated for their ability to produce ethanol, from the selected starting material, using knowledge gained about their activity. In particular, efficiency of hydrolysis, synergy with other enzymes and enzyme recyclability will be assessed, in pilot scale trials.
Initially a pilot-scale plant will be developed. However, the starting materials, wheat straw, bran and spruce, are found in abundance throughout Europe as waste materials, so it is hoped that the DISCO project will lead to full scale-plants producing biofuels across the continent.
Libraries of microorganisms are a key resource for the research community, and the DISCO project is making full use of them. For example, the Budapest University of Technology and Economics (BUTE), a partner in the DISCO project, holds a library of more than 4,000 different microorganisms obtained from a multitude of different sources. From these a number of promising candidates for lignocellulosic enzyme activity have already been identified and are being further characterized in the labs of other DISCO project partners.
The DISCO project is a collaboration between research institutes, universities and industrial partners drawn from across Europe and Russia. Participants include:
- GR Wright and Sons Ltd (UK)
- Sekab E-Technology (Sweden)
- Dyadic (Netherlands)
- Biogold Ou (Estonia)
- Cooperatie Cehave Landbouwbeland U.A. (Netherlands)
- A.N. Bakh Institute of Biochemistry of the Russian Academy of Science (Russia)
- Helsingin Yliopisto (Finland
- Wageningen Universiteit (Netherlands)
- Budapest Muszaki Es Gazdasagtudomanyi Egyetem (Hungary)
- Institute of Food Research (UK)
We’re looking to nature to find answers to the problem of efficiently generating next-generation biofuels from renewable sources, in this case from abundant waste materials from farming and industry. That answer could literally be lying in the soil, in an undiscovered and uncharacterized microorganism.—Professor Kristiina Kruus, Technical Research Centre of Finland (VTT), DISCO coordinator
The €4-million (US$5.5-million) project (€2.99 million in FP7 funding) began in August 2008, and will conclude in July 2012.