UNAIR NEWS – Cellulolytic microbes such as bacteria, mold, fungi and protozoa are cellulase-producing enzymes. This enzyme is capable of hydrolyzing the β-1,4 glycoside bond in cellulose, a polysaccharide structure that is abundant in plants.
Cellulase enzymes are classified into 2 groups, exocellulase and endocellulase. Exocellulase can be secreted by microbes so it is free in the digestive tract of animals, whereas endocellulase is present in the microbial body and must be excreted in vitro by sonication.
This cellulase enzyme potential was the research background of the lecturer at Faculty of Veterinary Medicine (FKH) Dr. Widya Paramita Lokapirnasari MP., drh and her team. Her research aims to identify cellulolytic isolates originating from cow rumen liquid waste from slaughterhouses (RPH) through testing the activity of cellulolytic enzymes.
“The parameters observed in the research include the activity of endoglucanase, exoglucanase and β-glucosidase. Genotype testing was also carried out through the 16S rDNA test and biochemical identification using VITEK 2 microbial identification system version : 05.01 (BioMérieux),” she said.
The isolated bacterial DNA, she continued, was then amplified in vitro by the PCR method. Furthermore, the sequencing of 16S rDNA fragment nucleotides was determined by using GenBank data to identify bacterial samples.
Bacteria that are classified as cellulolytic bacteria are based on their ability to grow on Carboxyl Methyl Cellulose (CMC) selective media. The ability to utilize cellulose is also based on the formation of clear zones on CMC media with congo red staining.
The presence of clear zones on CMC media showed the ability of microbes to utilize cellulose. The growth ability showed that the bacteria Enterobacter cloacae is able to utilize cellulose as a source of its nutrients.
“The results of enzyme activity using specific substrates indicate that cellulolytic isolates had an activity on endo- (1,4) -β-D-glucanase enzyme activity of 2.0617 x 10 -1 U / ml, exo- (1,4) -β D-glucanase activity at 2,2400 x 10 -1 U / ml while β-glucocidase enzyme activity at 2,7000 x 10 -1 U / ml. The cellulolytic isolate was further tested with 16S-DNA and phylogenetic tree structure on 82 isolates with 97-99% similarity level,” she explained.
The majority of bacteria that are similar to these isolates are from the Genus Enterobacter. Based on the similarity of the nucleotide structure, it is close with Enterobacter cloacae subs cloacae ATCC 13047 and the properties in accordance with the microbial identification system, the isolate was identified as Enterobacter cloacae SAR 01.
Author: Dian Putri Apriliani
Editor: Nuri Hermawan
Andreas, B.Y., W.P. Lokapirnasari, R.Najwan, K. Huda, H.C.P, Wardhani, dan N.F.N, Rohman. 2019. Characterization of Cellulolytic Bacteria as Candidate Probiotic for Animal. Indian Veterinary Journal, 96(08): 29-31.