T. Q. Truong¹*, K. D. Nguyen²

¹Faculty of Agriculture – Fisheries, University of Cuu Long, Vinh Long, Vietnam;
²Faculty of Biotechnology, Ho Chi Minh City Open University, Ho Chi Minh City, Vietnam;
*e-mail: truongquoctat@mku.edu.vn

Received: 24 January 2026; Revised: 25 February 2026;
Accepted: 03 April 2026; Available on-line: April 2026

Cellulase derived from cellulolytic bacteria plays an increasingly important role in biotechnology and is characterized by hight consumption demand on the global enzyme market. Bacterial strains of the genus Bacillus have been reported to be capable of synthesizing cellulase, which breaks β-1,4-glycosidic bonds, releasing glucose as the end product. Nevertheless, enzyme activity and yield are affected by many factors, especially by bacterial strain and culture medium conditions. This study aimed to assess Bacillus subtilis DSC.03 cellulase activity depending on the strain cultivation parameters. Bacillus subtilis DSC.03 was isolated from durian peel compost samples. Carboxymethyl cellulase (CMC) activity was determined by reaction with 3,5-dinitrosalicylic acid in the crude enzyme extract of the bacterial strain. It was shown that cultivation time, temperature and substrate concentration have a significant impact on the CMCase activity of DSC.03. The optimal parameters were as follows: 60 h at 40℃, 1% carboxymethyl cellulose and 2% inoculum. Under these conditions the strain exhibited a maximum CMCase activity of 1.72 U/ml.