Irpex lacteus DSM 1183 growing on yeast malt peptone glucose agar [Photo credit: Teeratas Kijpornyongpan]

Irpex lacteus is a saprotrophic white-rot fungus belonging to the order Polyporales. White-rot fungi have the capability to degrade all the structural components of plant biomass, including cellulose, hemicellulose, and lignin. White-rot fungi are divided into two groups based on degradation patterns – those that selectively degrade lignin first, and those that degrade all the lignocellulosic components simultaneously. This specific strain of I. lacteus degrades all the plant components simultaneously. This degradation pattern has been demonstrated in cultivations containing poplar or corn stover as the sole carbon source. These lignocellulosic feedstocks are potential substrates in the bioenergy industry.

White-rot fungi are considered the most efficient lignin degrading organisms in nature. However, pathway elucidation for the catabolism of lignin-derived aromatic compounds towards central metabolism is still in its infancy. The genome sequencing of the dikaryotic strain Irpex lacteus DSM 1183 will be essential for comparative and targeted systems biology studies focused on elucidating intracellular pathways during the degradation of lignin and lignin-derived aromatic compounds. Understanding the mechanisms that this fungus utilizes for lignin conversion will be also key to provide further biological insights for lignin valorization efforts.