from the same wild strain QM6A isolated for the USA army laboratory (Esterbauer
et al. 1991). In general, random mutagenesis has been incapable of bringing
overproducer lignocellulose degrading organisms perhaps because cellulose degradation is a very coordinated genetic and biochemical process.
7.6.3 Molecular Biology
Although some progress has been made using random mutagenesis methods,
molecular biology along with protein engineering techniques seems more suitable
to allow the organized improvement in enzyme production, and enzyme activity
along with the pH and temperature resistance necessary to get a real increase in
lignocellulotic degradation needed to reach sustainable process from lignocellulosic biomass. It is possible to improve genes by directed mutagenesis, get catalytic sites with a better substrate access, simpler protein folding patters, or
synthesize new enzymes genes engineered for a given substrate by computer
assisted design. In silico experiments will take relevance to test any enzyme in
simulated environments in order to improve its characteristics before using it in
real life. Another interesting possibility is multifunctional enzymes, in which
several different or even sequential enzymatic activities can be integrated in a
single protein molecule; there are many interesting reported cases as a bifunctional
exoglucanase–endoglucanase (Warren et al. 1986), a chimeric endoglucanases–
xylanase (Tomme et al. 1994), and special mention is deserved for the endoglucanase, cellobiohidrolase, and xylanase activity enzymes reported by Aylward
et al. (1999). Another interesting enhancement is the improved thermostability of
recombinant manganese peroxidase by engineering of disulfide bridge stability
(Reading and Aust 2000).
Combination of genetic and recombinant DNA has allowed the construction of
improved strains as T. reesie RUT-P 37 that has double cellulase specific activity
compared to QM6 the original wild strain (Montenecourt et al. 1983) or T. reesei
CL 847 strain resistant to catabolite repression that has a fourfold increase in
cellulose productivity compared to wild strain. (Durand and Clanet 1988). It is
necessary to include all techniques in a coordinated way to overcome the bounds
to lignocellulose degradation that is a result of the complex structural nature of
biomass.
7 Integral Management of Lignocellulosic Biomass by Biorefining
243
et al. 1991). In general, random mutagenesis has been incapable of bringing
overproducer lignocellulose degrading organisms perhaps because cellulose degradation is a very coordinated genetic and biochemical process.
7.6.3 Molecular Biology
Although some progress has been made using random mutagenesis methods,
molecular biology along with protein engineering techniques seems more suitable
to allow the organized improvement in enzyme production, and enzyme activity
along with the pH and temperature resistance necessary to get a real increase in
lignocellulotic degradation needed to reach sustainable process from lignocellulosic biomass. It is possible to improve genes by directed mutagenesis, get catalytic sites with a better substrate access, simpler protein folding patters, or
synthesize new enzymes genes engineered for a given substrate by computer
assisted design. In silico experiments will take relevance to test any enzyme in
simulated environments in order to improve its characteristics before using it in
real life. Another interesting possibility is multifunctional enzymes, in which
several different or even sequential enzymatic activities can be integrated in a
single protein molecule; there are many interesting reported cases as a bifunctional
exoglucanase–endoglucanase (Warren et al. 1986), a chimeric endoglucanases–
xylanase (Tomme et al. 1994), and special mention is deserved for the endoglucanase, cellobiohidrolase, and xylanase activity enzymes reported by Aylward
et al. (1999). Another interesting enhancement is the improved thermostability of
recombinant manganese peroxidase by engineering of disulfide bridge stability
(Reading and Aust 2000).
Combination of genetic and recombinant DNA has allowed the construction of
improved strains as T. reesie RUT-P 37 that has double cellulase specific activity
compared to QM6 the original wild strain (Montenecourt et al. 1983) or T. reesei
CL 847 strain resistant to catabolite repression that has a fourfold increase in
cellulose productivity compared to wild strain. (Durand and Clanet 1988). It is
necessary to include all techniques in a coordinated way to overcome the bounds
to lignocellulose degradation that is a result of the complex structural nature of
biomass.
7 Integral Management of Lignocellulosic Biomass by Biorefining
243