Abstract
Halophilic bacteria are promising for biofuel production due to their efficient cellulose degradation. Their cellulases exhibit high activity even in the presence of inhibitors and under extreme conditions, making them ideal for biorefinery applications. In this study, we isolated a strain of Halomonas elongata (Kadal6) from decomposed cotton cloth on the Rameshwaram seashore. Morphological, biochemical, and 16S rRNA analyses revealed that Kadal6 was 99.93% similar to the cellulase-producing strain H. elongata MH25661. The tolerance of the cellulase to inhibitors was assessed through molecular docking with a cellulase model of MH25661 generated by I-TASSER, and experimentally using response surface methodology with Kadal6. A molecular docking study indicated a high inhibition constant for ethanol, hydroxymethylfurfural (HMF), and furfural. The cellulase enzyme from H. elongata Kadal6 (CellHe) showed a maximum inhibition rate of 44.27% at 55 °C, 15% ethanol, and 6.5 g/L furfural and HMF. The enzyme retained 50% of its activity in the presence of these inhibitors, and remained unaffected at 1 g/L furfural and HMF, although inhibition occurred at 3 g/L. H. elongata cellulase demonstrated significant tolerance to inhibition both in vitro (RSM) and in silico, indicating its potential for biorefinery applications in harsh environments.
Halophilic bacteria are promising for biofuel production due to their efficient cellulose degradation. Their cellulases exhibit high activity even in the presence of inhibitors and under extreme conditions, making them ideal for biorefinery applications. In this study, we isolated a strain of Halomonas elongata (Kadal6) from decomposed cotton cloth on the Rameshwaram seashore. Morphological, biochemical, and 16S rRNA analyses revealed that Kadal6 was 99.93% similar to the cellulase-producing strain H. elongata MH25661. The tolerance of the cellulase to inhibitors was assessed through molecular docking with a cellulase model of MH25661 generated by I-TASSER, and experimentally using response surface methodology with Kadal6. A molecular docking study indicated a high inhibition constant for ethanol, hydroxymethylfurfural (HMF), and furfural. The cellulase enzyme from H. elongata Kadal6 (CellHe) showed a maximum inhibition rate of 44.27% at 55 °C, 15% ethanol, and 6.5 g/L furfural and HMF. The enzyme retained 50% of its activity in the presence of these inhibitors, and remained unaffected at 1 g/L furfural and HMF, although inhibition occurred at 3 g/L. H. elongata cellulase demonstrated significant tolerance to inhibition both in vitro (RSM) and in silico, indicating its potential for biorefinery applications in harsh environments.
Graphical abstract
Highlights
- The resistance of the isolated strain to inhibition was assessed using response surface methodology and molecular docking analysis.
- In silico analysis revealed that CellHe possesses favorable industrial traits for biofuel production and showed tolerance to ethanol, HMF, and furfural, which are crucial for efficient cellulose hydrolysis.
- Cellulase was predicted to have a maximum inhibition rate of 44.27%, that is, cellulase remained approximately 50% active after exposure to inhibitory compounds under harsh conditions.
- Halomonas elongata strain kadal6, isolated from partially decomposed cotton cloth at the seashore of Rameshwaram, shows a strong capacity for the breakdown of cellulose into glucose molecules.
Keywords: Halomonas elongata, cellulase, molecular docking, response surface methodology
SDG Keywords: SDG7, SDG14
- Narayanan, Aathimoolam, Kanimozhi Jeyaram, Ashish A. Prabhu, Sundar Krishnan, Selvaraj Kunjiappan, Nareshkumar Baskaran, and Dharanidharan Murugan. "Cellulase from Halomonas elongata for biofuel application: enzymatic characterization and inhibition tolerance investigation." Preparative Biochemistry & Biotechnology (2025): 1-18.
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