The process of decomposition of biomass is highly complex, involving the activities of a mixed microflora and fauna. One of the difficulties in understanding of the mechanisms in decomposition of biomass is that we do not know the structure of the plant cell wall—the chief constituent of the biomass—which varies from plant to plant and changes with age and from season to season. An "old" hypothesis that wood-decay fungi employ extracellular reactive oxygen species and oxidoreductase enzymes to cleave lignocellulose is receiving renewed attention. Clues may come from the study of the morphology and physiology of a fungus when growing and degrading an insoluble polymer than when it is growing on their derived (soluble) products. To date, studies have concentrated on the degradation of polymers in shake-flask cultures and the role of adhesion of microorganisms to substrate has received little attention. The mucilage sheath associated with fungal hyphae in material decaying in vivo may be important because considerable enzyme activity could be located at the surface of hyphae. Few studies have compared the rates of biomass decomposition by pure cultures with those with mixed cultures. Finally, it is quite seriously suggested to engineer a single organism or to use a mixed culture of organisms with the ability to utilize cellulose and hemicelluloses, and for utilization of the resulting products for conversion into ethanol to use as a fuel. This otherwise attractive scheme could have disastrous consequences if it leads to deforestation due to the harvesting of trees and plants for cellulose fibers.
Was this article helpful?