Biomedical Engineering Reference
In-Depth Information
simply divided into two types: physical crushing to obtain small particles and make
further conversion easy; and chemical decomposition to obtain a component or
mixed component for preparing final products. For physical crushing purposes, a
particle size analyzer could be used to appraise the crushing results. For assaying the
separation or selective fractionation of components, Fourier transform near-infrared
diffuse reflectance spectroscopy could be used [
21
].
11.2
Research Methods for the Microbial and Enzymatic
Hydrolysis Process of Lignocellulosic Materials
11.2.1
Introduction
Many microorganisms in nature can use cellulose or hemicellulose as a carbon
and energy source, maintaining the circulation of the carbon element. Cellulose-
degrading microbes are diverse, which provides a realistic basis for screening
cellulose-degrading strains from nature. Since Pringsheim isolated cellulose-
decomposing bacteria from the soil in 1912 for the first time, research on various
cellulose-degradating microorganisms and their product cellulase has made great
progress. A large amount of cellulose-degrading microorganisms and their product
cellulase is separated and purified. Cellulase is distributed widely because many
fungi, bacteria, and actinomycetes can produce cellulase under certain conditions.
Recently, cellulase was found in succession from archaea. A degradation strategy
presents diversity because of different cellulose-degrading microorganisms [
22
].
11.2.2
Research Methods of Resource Science for Cellulose
Degradation Microorganisms
11.2.2.1
Screening and Identification Methods for Culturable
Cellulose-Degrading Microorganisms
1. Screening methods for cellulose-degrading microorganisms
According to the special nutritional requirement and metabolite products of
microorganisms, the objective colony can be easily found from mixed flora through
the design of appropriate selective media and differential media.
(1) Screening of cellulase-producing bacteria: Congo red staining method [
23
,
24
]
Congo red could form a red complex with cellulose in medium. When cellulose is
decomposed by cellulase, Congo red-cellulose complexes would not be formed. A
transparent circle around cellulose decomposition microorganisms will appear in the
medium. So, cellulose-degrading microorganisms could be screened by presentation
of a transparent circle. The rich medium used is composed of 2.0 g K
2
HPO
4
,
