Change of Endoglucanase Activity and Rumen Microbial Community During Biodegradation of Cellulose Using Rumen...

Area of Science:

• Microbiology
• Biochemistry
• Enzymology

Background:

• Rumen microorganisms are crucial for degrading lignocellulosic biomass, a key process in methane fermentation.
• The specific roles of endoglucanases in lignocellulose digestion by rumen microbes are not fully understood.

Purpose of the Study:

• To investigate the contribution of different endoglucanases to cellulose degradation by rumen microorganisms.
• To correlate the activity of specific endoglucanases with microbial community shifts during carboxymethyl cellulose (CMC) degradation.

Main Methods:

• Zymogram analysis to identify and quantify endoglucanase activities.
• Metagenomic analysis to assess changes in microbial community composition.
• Correlation analysis between enzyme activities and microbial abundances.

Main Results:

• CMC degradation rate increased over 24 hours.
• Endoglucanases of 52 and 53 kDa were highly active in the first 12 hours, while 42, 50, and 101 kDa enzymes showed higher activity from 12 to 24 hours.
• Shifts in microbial populations, including decreases in *Selenomonas*, *Eudiplodinium*, *Metadinium* and increases in *Porphyromonas*, *Didinium*, Bacteroidetes, *Clostridiales*, *Lachnospiraceae*, and *Sphingobacteriaceae*, correlated with specific endoglucanase activities.

Conclusions:

• A dynamic interplay exists between different endoglucanases and specific microbial groups during CMC degradation.
• Uncharacterized or non-dominant microorganisms likely produce key endoglucanases (40, 50, 52, 53, 101 kDa) that enhance lignocellulose breakdown in the rumen.