Optimization and biochemical characterization of a thermotolerant processive cellulase, PtCel1, of Parageobacillus thermoglucosidasius NBCB1

• Published in: Journal of basic microbiology Vol. 63; no. 3-4; pp. 326 - 339
• Main Authors: Basak, Arijita, Gavande, Parmeshwar V., Murmu, Nensina, Ghosh, Shilpi
• Format: Journal Article
• Language: English
• Published: Germany 01.03.2023
• Subjects: algorithms; bacterial culture; calcium; Cellulase - metabolism; cellulose; Cellulose - metabolism; culture media; endo-1,4-beta-glucanase; Fermentation; glucose; heat tolerance; lignocellulose; magnesium; mannose; metal; microbiology; molecular weight; neural networking; protein purification; rice straw; sodium; sodium dodecyl sulfate; submerged fermentation; Temperature; thermal stability; thermotolerance; vermicompost; vermicomposting; vermicomposts; zinc; metal; protein purification; neural networking; thermotolerance; vermicompost
• ISSN: 0233-111X; 1521-4028; 1521-4028
• DOI: 10.1002/jobm.202200394

Vermicomposting involves enrichment of microorganisms that are able to resist higher temperatures and perform simultaneous degradation of lignocellulose, and therefore, such microbial communities are a potential source of cellulolytic enzymes. This study aimed to optimize the production of a processive cellulase by Parageobacillus thermoglucosidasius NBCB1 isolated from vermicompost, under submerged fermentation of rice straw and to characterize the purified enzyme for industrial suitability. Cellulase production in basal medium (7.27 IU/mg) was enhanced to 61 IU/mg by One Factor At a Time approach, which was further improved to 78.46 IU/mg by genetic algorithm based artificial neural networking. The cellulase PtCel1 purified from bacterial culture showed a molecular weight of ≈33 kD, had activity on both crystalline (305 IU/mg) and amorphous (184 IU/mg) cellulose as substrates. It had pH and temperature optima of 5.5°C and 60°C, respectively, and retained 100% activity upon preincubation at 60°C for 1 h indicating thermostability. PtCel1 was tolerant to sodium dodecyl sulfate, glucose and mannose; and the various metal chlorides, such as sodium, magnesium, calcium and zinc, acted as inducers giving 77.54%, 45.15%, 61.10%, and 169.14% augmentation of activity, respectively. Its efficiency on cellulosic substrates and robustness against aforementioned chemical and thermal environment makes it suitable for industrial applications.