Utilization of sea water based media for the production and characterization of cellulase by Fusarium subglutinans MTCC 11891

The present study focuses on isolation, screening and identification of fungal strain capable of producing cellulase enzyme in sea water based media from paddy fields of Rourkela, Odisha, India. The filamentous fungi isolated were identified as Fusarium subglutinans MTCC 11891. Cellulase enzyme was characterized for its optimal pH and temperature and also studied for the effect of metal ions on enzyme activity. Comparative studies were carried out using both fresh and sea water based media in order to investigate the salt tolerance level of cellulase produced by the fungal strain. The fungal strain was found to be halotolerant with optimal pH of 5.0 with cellulase activity of 292.53U/mL and 184U/mL in fresh and sea water based Mandel's media, respectively. The optimal temperature for F. subglutinans MTCC 11891 cellulase was recorded at 80°C with 347.43U/mL for fresh water and 232U/mL for sea water based Mandel's media. Manifold increase in cellulase activity was evidenced in the presence of 5mM Mn2+ and Fe2+ concentration in both fresh and sea water based Mandel's media suggesting these two cations as key catalytic molecules. Partial purification of the cellulase produced in fresh water based Mandel's media was performed using diethylaminoethanol (DEAE)-Sepharose column and the fraction with enzyme activity of 298.68U/mL was recorded as fraction with highest cellulase concentration. Halotolerant cellulases would be more useful in future for the development of sea water based systems to produce bioethanol.