5-08: Engineering filamentous fungi for increased production of lignocellulose-derived lipids

The majority of biodiesel produced in the United States is derived from oilseed crops such as soybean and rapeseed. The acreage of these oilseed crops that is required to displace a significant fraction of diesel is beyond current sustainable production capacity. Alternative technologies are required to make biodiesel a sustainable, renewable option. We propose to use a celluloytic filamentous fungus to directly produce lipids from a lignocellulosic feedstock. In this study, Neurospora crassa is used as a model system to investigate the production of lignocellulose-derived lipids, whereby our ultimate goal is to develop an approach to redesign any cellulolytic fungus to achieve maximal lipid production from lignocellulosic biomass.

This work uses two complementary approaches to understand the mechanism of lipid over-production in the model filamentous fungus N. crassa. A forward genetic approach aims to characterize lipid over-production by identifying the mutations in a morphological mutant of N. crassa that are responsible for the hyper-lipid accumulating phenotype. A reverse genetic approach aims to improve lipid production and accumulation in N. crassa by redirecting carbon toward fatty acid biosynthesis by removing competing carbon storage pathways and by eliminating fatty acid degradation. Targets for improving lipid accumulation have been identified. Additionally, we demonstrate the feasibility of lipid production directly from a lignocellulosic feedstock using a cellulolytic filamentous fungus as a biological catalyst.