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Application of ZnO Nanoparticles for Improving the Thermal and pH Stability of Crude Cellulase Obtained from Aspergillus fumigatus AA001.

Srivastava N, Srivastava M, Mishra PK, Ramteke PW - Front Microbiol (2016)

Bottom Line: Cellulases are the enzymes which are responsible for the hydrolysis of cellulosic biomass.The crude thermostable cellulase has been obtained from the Aspergillus fumigatus AA001 and treated with ZnO nanoparticle which shows thermal stability at 65°C up to 10 h whereas it showed pH stability in the alkaline pH range and retained its 53% of relative activity at pH 10.5.These findings may be promising in the area of biofuels production.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Engineering, Sam Higginbottom Institute of Agriculture Technology & SciencesAllahabad, India; Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University)Varanasi, India.

ABSTRACT
Cellulases are the enzymes which are responsible for the hydrolysis of cellulosic biomass. In this study thermal and pH stability of crude cellulase has been investigated in the presence of zinc oxide (ZnO) nanoparticles. We synthesized ZnO nanoparticle by sol-gel method and characterized through various techniques including, X-ray Diffraction, ultraviolet-visible spectroscope, field emission scanning electron microscope and high resolution scanning electron microscope. The crude thermostable cellulase has been obtained from the Aspergillus fumigatus AA001 and treated with ZnO nanoparticle which shows thermal stability at 65°C up to 10 h whereas it showed pH stability in the alkaline pH range and retained its 53% of relative activity at pH 10.5. These findings may be promising in the area of biofuels production.

No MeSH data available.


Effect of ZnO nanoparticles (7.5 μg/mL) on pH stability of crude cellulase.
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Figure 5: Effect of ZnO nanoparticles (7.5 μg/mL) on pH stability of crude cellulase.

Mentions: Effect of ZnO nanoparticles on the pH stability of the crude cellulase has been investigated at different pH ranges and depicted in Figure 5. It was observed that the enzyme was stable and retained its complete relative activity at pH 7.5 which was continued to stable in the presence of ZnO nanoparticles at pH 8.0. Further, the pH stability of ZnO nanoparticles treated cellulase was decreased with increase in the pH value and it retained its 67 and 53% of relative activity at pH 10 and 10.5. However, the enzyme retained its 39 and 10% of relative activity at pH 11 and 12 (with significance level of 1.0%). Nevertheless, when compared to control, the ZnO nanoparticles treated cellulase showed better performance by maintaining its half-life at pH 10.5 whereas it was observed that the untreated cellulase retained its 52 and 32% of relative activity at pH 8.0 and 8.5, respectively. Additionally, the untreated cellulase retained non-considerable relative activity beyond the pH 8.5 (data not shown). These results clearly indicated the potential role of ZnO nanoparticles to improve the pH stability and efficiency of crude cellulase enzyme. In addition, ZnO nanoparticles having a high isoelectric point (IEP ~9.5) is suitable for the adsorption of low IEP enzymes such as cellulase (IEP ~4.5) and this could probably be a reason for the improved alkali stability of ZnO nanoparticles treated celluase by providing a friendly micro-environment to retain its stability (Wang et al., 2013).


Application of ZnO Nanoparticles for Improving the Thermal and pH Stability of Crude Cellulase Obtained from Aspergillus fumigatus AA001.

Srivastava N, Srivastava M, Mishra PK, Ramteke PW - Front Microbiol (2016)

Effect of ZnO nanoparticles (7.5 μg/mL) on pH stability of crude cellulase.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834293&req=5

Figure 5: Effect of ZnO nanoparticles (7.5 μg/mL) on pH stability of crude cellulase.
Mentions: Effect of ZnO nanoparticles on the pH stability of the crude cellulase has been investigated at different pH ranges and depicted in Figure 5. It was observed that the enzyme was stable and retained its complete relative activity at pH 7.5 which was continued to stable in the presence of ZnO nanoparticles at pH 8.0. Further, the pH stability of ZnO nanoparticles treated cellulase was decreased with increase in the pH value and it retained its 67 and 53% of relative activity at pH 10 and 10.5. However, the enzyme retained its 39 and 10% of relative activity at pH 11 and 12 (with significance level of 1.0%). Nevertheless, when compared to control, the ZnO nanoparticles treated cellulase showed better performance by maintaining its half-life at pH 10.5 whereas it was observed that the untreated cellulase retained its 52 and 32% of relative activity at pH 8.0 and 8.5, respectively. Additionally, the untreated cellulase retained non-considerable relative activity beyond the pH 8.5 (data not shown). These results clearly indicated the potential role of ZnO nanoparticles to improve the pH stability and efficiency of crude cellulase enzyme. In addition, ZnO nanoparticles having a high isoelectric point (IEP ~9.5) is suitable for the adsorption of low IEP enzymes such as cellulase (IEP ~4.5) and this could probably be a reason for the improved alkali stability of ZnO nanoparticles treated celluase by providing a friendly micro-environment to retain its stability (Wang et al., 2013).

Bottom Line: Cellulases are the enzymes which are responsible for the hydrolysis of cellulosic biomass.The crude thermostable cellulase has been obtained from the Aspergillus fumigatus AA001 and treated with ZnO nanoparticle which shows thermal stability at 65°C up to 10 h whereas it showed pH stability in the alkaline pH range and retained its 53% of relative activity at pH 10.5.These findings may be promising in the area of biofuels production.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Engineering, Sam Higginbottom Institute of Agriculture Technology & SciencesAllahabad, India; Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University)Varanasi, India.

ABSTRACT
Cellulases are the enzymes which are responsible for the hydrolysis of cellulosic biomass. In this study thermal and pH stability of crude cellulase has been investigated in the presence of zinc oxide (ZnO) nanoparticles. We synthesized ZnO nanoparticle by sol-gel method and characterized through various techniques including, X-ray Diffraction, ultraviolet-visible spectroscope, field emission scanning electron microscope and high resolution scanning electron microscope. The crude thermostable cellulase has been obtained from the Aspergillus fumigatus AA001 and treated with ZnO nanoparticle which shows thermal stability at 65°C up to 10 h whereas it showed pH stability in the alkaline pH range and retained its 53% of relative activity at pH 10.5. These findings may be promising in the area of biofuels production.

No MeSH data available.