Aerobic deconstruction of cellulosic biomass by an insect-associated Streptomyces

Abstract

Streptomyces are best known for producing antimicrobial secondary metabolites, but they are also recognized for their contributions to biomass utilization. Despite their importance to carbon cycling in terrestrial ecosystems, our understanding of the cellulolytic ability of Streptomyces is currently limited to a few soil-isolates. Here, we demonstrate the biomass-deconstructing capability of Streptomyces sp. SirexAA-E (ActE), an aerobic bacterium associated with the invasive pine-boring woodwasp Sirex noctilio. When grown on plant biomass, ActE secretes a suite of enzymes including endo- and exo-cellulases, CBM33 polysaccharide-monooxygenases, and hemicellulases. Genome-wide transcriptomic and proteomic analyses, and biochemical assays have revealed the key enzymes used to deconstruct crystalline cellulose, other pure polysaccharides, and biomass. The mixture of enzymes obtained from growth on biomass has biomass-degrading activity comparable to a cellulolytic enzyme cocktail from the fungus Trichoderma reesei, and thus provides a compelling example of high cellulolytic capacity in an aerobic bacterium.

Antifungal actinomycetes associated with the pine bark beetle, Orthotomicus erosus, in South Africa

“…SPB074) 13,28 and another clade that contained two branches, one with the eight isolates from this study and the other a clade with isolates from Sirex noctilio (Streptomyces sp. SA3ActG) 29 and D. frontalis (Streptomyces spp. SPB074) 28 .…”

Bacterial genomes: what they teach us about cellulose degradation

“…Advanced systems such as genome-wide transcriptomic and proteomic analyses of cellulolytic organisms will be utilized to identify subsets of GH family members intimately involved in cellulose degradation [71][72][73];…”

Diversity of Two-Domain Laccase-Like Multicopper Oxidase Genes in Streptomyces spp.: Identification of Genes Potentially Involved in Extracellular Activities and Lignocellulose Degradation during Composting of Agricultural Waste

“…Some Streptomyces isolates participate in the degradation of recalcitrant biopolymers such as lignin, hemicelluloses, or celluloses found in wood (8)(9)(10). Ulrich et al (7) reported that Streptomyces spp.…”