Biomedical Engineering Reference
In-Depth Information
9.2
Application in Environmental Protection
Natural lignocellulosic materials are the most abundant renewable biomass on earth;
microbial degradation and transformation of them is the main aspect of the carbon
cycle in nature. The effective utilization of this process not only can offer cheap
raw materials for agriculture, feed, light industry, and the chemical industry, but
also can play an important role in the protection from environmental pollution and
establishment of a healthy ecosystem.
9.2.1
Application of White-Rot Fungi
The white-rot fungi are fungal groups that vary greatly. They can degrade all
components of the cell wall, including lignin, no matter the location. They will cause
the corrosion of the cell wall with the presence of the mycelia. With the degradation
process, a larger gap would be formed, which is often filled with mycelia; the fungi
that cause this type of white corrosion are often considered to be nonselective and
facultative white-rot fungi. Some kinds of white-rot fungi show high degradability
of lignin but a low value for cellulose.
White-rot fungi have an important role in the degradation of organic pollutants.
Because many organic pollutants have a similar structure as the lignin structural unit,
the degradation of various organic pollutants (mainly aromatic organic compounds)
in industrial wastewater by white-rot fungi has become an important research
direction. Research showed that white-rot fungi not only could degrade structural
analogues of lignin but also could degrade a variety of other organic compounds,
including PCBs (polychlorinated biphenyls). This work caused a great deal of
attention in both academia and industry. Because of the strong financial support
from industry, the research and application of white-rot fungi and its technology
have achieved great development within last 10 years; its influence has expanded
increasingly and gradually shifted from the research laboratory to industrial appli-
cations. In this area, research in China started in the 1990s, which was almost
20 years later than some countries. Therefore, it is necessary to have distinctive and
innovative research work according to China's national conditions, learning from
worldwide experience.
9.2.1.1
Advantages of White-Rot Fungi for Environmental Control
Compared with other organisms, especially bacteria, white-rot fungi have the
following advantages for environmental control.
(1) Bacteria could synthesize the desired degrading enzyme only when induced by
a certain concentration of substrate. So, they cannot degrade organic pollutants
in low concentrations and can only reduce the pollutants to a limited level.
