Biomedical Engineering Reference
In-Depth Information
of animal and plant remains, biotransformation, and material recycling. Now, the
material circulation mechanism and its application is garnering increased attention.
At the Changbai Mountain Forest Ecosystem Research Station, Inner Mongolia
Grassland Ecosystem Research Station, and Xining plateau meadow ecosystem
positioning station, research has been carried out on the material cycle, the types
of microbial ecosystem, distribution, succession, substance transformation, and
ecological factors on the decomposition rate of dried tree leaf litter. Research also
included looking for ways to improve the forest, pasture, and meadow productivity
in terms of cellulose microorganism ecology.
With the rapid development of economic construction, the microbial ecology
studies will proceed more widely and deeply. The development of microbial ecology
and cellulose microbial ecology engenders mutual promotion and constraints.
With the progress of ecological engineering and biological engineering, cellulose
microbial ecology will play an increasingly more important role in environmental
information systems, the relationship in coordination with human resources and the
environment, and development and utilization of rich cellulose sources.
In the research process of cellulose microbial ecology, it was discovered that
cellulose microbes were extensive in nature. Bacteria, actinomycetes, fungi, and
basidiomycetes all can produce cellulase. Each type of cellulose-decomposing
microorganism shows different abilities to hydrolyze cellulose because of its differ-
ent cellulase systems and different enzymatic hydrolysis efficiency. People noticed
early on that microorganisms in the body of herbivorous animals have the unique
ability to break down cellulose. During a long period of time, the focus has been
on the study of anaerobic cellulose-decomposing bacteria. These bacteria generally
do not secrete extracellular enzymes, and the products are always acetic acid, CO
2
,
H
2
O, and so on. Later, study turned to aerobic cellulose-decomposing bacteria. In
1961, cellulase was first prepared from
Trichoderma
sp.
Trichoderma
cellulase has
three components: 1,4-
-
glucosidase. It has been the focus for a long time. Mary Mandels, a researcher from
Natick Research Institute, made a great contribution to the genetics of
Trichoderma
.
This researcher bred QM9414, MCG77, a series of cellulase superior strains. To
commemorate the pioneer Elwyn T. Reese, a researcher on cellulase from the United
States, a mutant was named
Enpenicillium javanicum
. Its CMC enzyme activity
is as great as QM9414, while
“
-D-glucose hydrolase, 1,4-
“
-D-glucan cellobiase, and
“
-glucosidase activity is not too high. In 1981, the
Hungarian Gyorgy Szakaes reported
Penicillium verrcubsum
WA30, a new screened
strain, which had higher cotton enzyme activity. In the early 1980s, Gao and Qu
from Shandong University of China isolated and screened
Penicillium paecilomyces
S28 and
Penicillium decumbens
JU1, which reached the international advanced level
of cellulase in the early 1980s. Then, by further mutagenesis the JU-A10 mutant
had higher cellulase activity, a relatively complete cellulase system, and a high
level of
“
-glucosidase enzyme activity. In 1980, Garcia-Martinez et al. used the
anaerobic bacterium
Clostridium thermocellum
to produce cellulase. In this, 95 %
of its
“
-glucosidase was extracellular enzymes, which was relatively rare. Zhang, a
researcher from the Chinese Academy of Forestry, Institute of Soil Science, studied
“
