Sunday, July 24, 2011
Grand Ballroom, 5th fl (Sheraton New Orleans)
Lignin is the second most abundant biopolymer, accounting to about a third of the total biomass on earth. Lignin is constructed via a random coupling of phenyl-propionoid units utilizing radical chemistry, making it one of the most heterogeneous biopolymers. Lignin, however, poses a problem in lignocellulosic fuel production. Due to its heterogeneous nature, enzymatic routes for lignin deconstruction are limited. Several enzymes from fungal sources have been implicated in having a role in lignin deconstruction, including manganese peroxidase, lignin peroxidase, and also the large laccase. On the other hand, the more genetically tractable actinomycetes have also been shown to degrade lignocellulosic matter. Small laccase from Streptomyces coelicolor was identified as a potential target for enzymatic routes to lignin deconstruction. In addition to the small laccase from S. coelicolor, we have both structurally and biochemically characterized two additional small laccases from S. viridosporus and Amycolatopsis sp. We have demonstrated that the bacterial small laccase can be utilized for lignin remodeling both in vivo and in vitro.