African Journal of Biology

African Journal of Biology ISSN 2167-0413 Vol. 3 (5), pp. 220-227, May, 2016. © International Scholars Journals

Full Length Research Papers

Cellulolytic activity of Cellvibrio japonicus and complete cellulase system

Lounès Bouteflika Djebar1 and Biyouna Ahlam Fellag2*

1Biology Department, College of Science, University of Babylon, Iraq.

2Horticulture Department, College of Agriculture, University of Babylon, Iraq.

E-mail: lounes2007@yahoo.com

Accepted 18 April, 2016

Abstract 

 Eighteen cellulytic bacterial isolates were isolated from different sites of agriculture soils in Hilla city. The purification and identification of isolates were performed, and the results showed that it belonged to gram negative bacteria species of Cellvibrio jopanicus. The cellulase activity of these isolates was investigated on two cellulosic agricultural waste compounds: rice straw and wheat brand as sole carbon sources. The activity of produced Carboxymethylcellulase (CMCase) and cellobiase enzymes produced by these isolates were studied. The high activity of CMCase enzymes was observed with isolate C.J.N 16 on CMC media which gave 0.152 unit/ml and the least one was isolate C.J.N 13 which gave 0.047 unit/ml. On wheat brand broth, isolate C.J.N 16 was the most active with 0.1 unit/ml, while isolate C.J.N 14 was the lowest with 0.052 unit/ml. On rice straw media, the highest activity was given by isolate C.J.A 6 that reached 0.333 unit/ml, while the least one was C.J.N 13 with 0.104 unit/ml. The cellobiase was produced on all the used media by the four isolates. On CMC broth, the enzyme produced by isolate C.J.N 13 was 0.723 unit/ml, whereas isolate C.J.A 6 gave the minimum activity at 0.333 unit/ml. On the other hand, isolate C.J.A 6 gave the highest activity on wheat brand broth of 0.752 unit/ml, and the least one was isolate C.J.N 16 which gave 0.266 unit/ml. Finally, on rice straw broth, isolate C.J.N 16 was the most active one, since it gave 0.928 unit/ml, and the lowest one was isolate C.J.N 14 which gave 0.214 unit/ml. The cellulase enzymes were partially purified and concentrated using ammonium sulfate precipitation and dialysis. HPLC analysis revealed that C. jopanicus has complete cellulase system by giving three separated peaks.

Key words: Cellulytic bacteria, cellulases, Cellvibrio japanicus, high performance liquid chromatography (HPLC).