Background

In order to decrease dependence on petroleum, the United States Department of Energy (USDOE) Office of the Biomass Program (OBP) is investing in research and development to enable its vision of the biorefinery. The biorefinery will decrease the use of petroleum through conversion of biomass such as crops or agricultural waste into fuels and products.

In 2004, the USDOE OBP asked researchers at the Pacific Northwest National Laboratory (PNNL) and the National Renewable Energy Laboratory (NREL) to prepare a list of the top ten building-block chemicals that can be derived from simple sugars by biological and/or chemical means. The resulting list of twelve building-block chemicals and the accompanying report (www.eere.energy.gov/biomass/pdfs/35523.pdf) form an informational foundation on which future DOE and industry bioproducts research will be built (Table 1.1).

How do fungi fit into the biorefinery? Analysis of the ‘top ten’ study indicates that nine of the top twelve chemical building blocks are currently produced, or may potentially be produced, by fungal fermentation processes. However, a significant barrier to the use of bio-based products is the economic feasibility – fuels and products must be price-competitive with those derived from petroleum. An obvious way to decrease the costs of biobased products from fungi is to make fermentation strains more productive and processes more efficient. Traditional strain improvement programmes typically span a timescale measured in decades and process development done through the use of batch cultures is extremely labour intensive.