Effect of Nickel–Cobaltite Nanoparticles on Production and Thermostability of Cellulases from Newly Isolated Thermotolerant Aspergillus fumigatus NS (Class: Eurotiomycetes)

Abstract

In the present study, effect of nickel-cobaltite (NiCo2O4) nanoparticles (NPs) was investigated on production and thermostability of the cellulase enzyme system using newly isolated thermotolerant Aspergillus fumigatus NS belonging to the class Euratiomycetes. The NiCo2O4 NPs were synthesized via hydrothermal method assisted by post-annealing treatment and characterized through X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. In the absence of NPs in the growth medium, filter paper cellulase (FP) activity of 18 IU/gds was achieved after 96 h, whereas 40 % higher FP activity in 72 h was observed with the addition of 1 mM concentration of NPs in the growth medium. Maximum production of endoglucanase (211 IU/gds), β-glucosidase (301 IU/gds), and xylanase (803 IU/gds) was achieved after 72 h without NPs (control), while in the presence of 1 mM concentration of NPs, endoglucanase, β-glucosidase, and xylanase activity increased by about 49, 53, and 19.8 %, respectively, after 48 h of incubation, against control, indicating a substantial increase in cellulase productivity with the addition of NiCo2O4 NPs in the growth medium. Crude enzyme was thermally stable for 7 h at 80 °C in presence of NPs, as against 4 h at the same temperature for control samples. Significant increase in the activity and improved thermal stability of cellulases in the presence of the NiCo2O4 NPs holds potential for use of NiCo2O4 NPs during enzyme production as well as hydrolysis. From the standpoint of biofuel production, these results hold enormous significance.

Extrolites of Aspergillus fumigatus and Other Pathogenic Species in Aspergillus Section Fumigati

“…It appears that when growing on plant compost these fungi need a certain profile of extrolites (small molecule extrolites and exoproteins), while as vertebrate opportunistic pathogens they may need quite a different profile of extrolites (Abad et al, 2010 ). For example cellulases would be important in the compost situation (Srivastava et al, 2014 ; Miao et al, 2015 ), while hemolysins are probably only important for the vertebrate infection process (Abad et al, 2010 ). The same would be the case for antifungals and antibiotics, especially anti-streptomycete metabolites, as A. fumigatus and other members of Aspergillus section Fumigati are thermotolerant / thermophilic species competing with other thermotolerant and thermophilic species of fungi and bacteria (Langarica-Fuentes et al, 2014 ).…”

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

“…Kamyar et al (2011) , reported the thermal stability of cellulase immobilized on superparamagnetic nanoparticles for 3 h at 60°C. In our earlier studies, we have reported the half-life of crude cellulase in the presence of NiCo 2 O 4 nanoparticles for 7 h at 80°C ( Srivastava et al, 2014b ) and ~56% at 70°C for 8 h in the presence of Fe 3 O 4 /Alginate nanocomposite ( Srivastava et al, 2015b ). Our results are in agreement with the report of Husain et al (2011) .…”

“…Furthermore, the multipoint attachment of the enzyme molecules on the surface of the nanomaterials can reduce the protein unfolding, resulting in the improved stability of the enzyme involved on the surface of nanoparticles ( Kamyar et al, 2011 ; Zhu et al, 2014 ). In our earlier studies, we have shown the effect of NiCo 2 O 4 , Fe 3 O 4 nanoparticles and Fe 3 O 4 /Alginate nanocomposite on the thermal stability of cellulase enzymes apart from its production and hydrolysis efficiency ( Srivastava et al, 2014b , 2015b ). Besides, improvement in stability, nanomaterial bound enzyme can also provide many advantages such as easy separation from the reaction mixture, less prone to contamination of product via the enzyme, continuous processing and the better product yield ( Wenjuan et al, 2015 ).…”

Nanomaterials Utilization in Biomass for Biofuel and Bioenergy Production

“…Another study has shown the use of nickel-cobaltite NPs on the stability of Aspergillus fumigatus cellulases at different concentrations of synthesized NPs. The results showed that the addition of 1 mM of nickel-cobaltite NPs increased enzyme activity of endoglucanase, β-glucosidase and xylanase by 49%, 53% and 19.8%, respectively [32]. Contrast to these, carbon nanotubes (CNTs) are widely known for their attractive features in electricity, thermal properties and mechanical strength [33].…”