Lignocellulose hydrolytic enzymes production byAspergillus flavusKUB2 using submerged fermentation of sugarcane bagasse waste

Abstract

Lignocellulosic wastes, rice straw, sugarcane bagasse, rice bran and sawdust, and pure commercial carboxymethyl cellulose (CMC) and xylan were used as substrates to cultivate cellulolytic fungus, Aspergillus flavus KUB2, in submerged fermentation at 30°C. Of all the substrates, sugarcane bagasse was a good source for the production of cellulolytic and also hemicellulolytic enzymes. The maximum activities of endoglucanase (CMCase), total cellulase (FPase) and xylanase using sugarcane bagasse as substrate were 8%, 75% and 165%, respectively, higher than those of the commercial substrates. The time course determination of enzyme production revealed that the highest CMCase (1.27 U/ml), FPase (0.72 U/ml) and xylanase (376.81 U/ml) activities were observed at 14 days of fermentation. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analyses confirmed the efficient structural alteration of sugarcane bagasse caused by enzymatic actions during A. flavus KUB2 cultivation. Based on the results of the hydrolytic enzyme activities, FTIR and SEM, A. flavus KUB2 is suggested as an efficient hydrolytic enzymes producer and an effective lignocellulose degrader, while sugarcane bagasse can be applied as a low-cost carbon source for the economical production of lignocellulose hydrolytic enzymes by A. flavus KUB2.

Biochemical Characterization of Cellulase From Bacillus subtilis Strain and its Effect on Digestibility and Structural Modifications of Lignocellulose Rich Biomass

“…In the case of SCB, the treatment has altered the architecture of the cell wall matrix components or removed the cellulose, lignin, and hemicellulosic components. Following bacterial and its enzyme treatment, similar alterations of several cracks were seen in SCB with a large number of holes, disordered fibers, and broken parallel stripes (Namnuch et al, 2021;Prajapati et al, 2020). A resemblant phenomenon was observed in other studies conducted on SCB hydrolysis with crude enzyme treatment (Matei et al, 2020;Ramarajan and Manohar, 2017).…”

One-Pot Ionic Liquid-Mediated Bioprocess for Pretreatment and Enzymatic Hydrolysis of Rice Straw with Ionic Liquid-Tolerance Bacterial Cellulase

“…It could be observed that most of the FT-IR spectra of both pretreated and untreated samples were similar, but some peaks were different in the intensities of transmittance and were related to the chemical bonds of cellulose, hemicellulose, and lignin. The heights of spectral peaks at 1515 cm −1 (representing aromatic skeletal vibrations of lignin [ 27 ]) and 1604 cm −1 (corresponding to stretching of aromatic benzene ring in lignin) were reduced in pretreated biomass compared to the untreated sample, indicating the removal of lignin content [ 28 ]. The transmittances of peaks at 1249 cm −1 and 1732 cm −1 corresponding to the C–O stretching and carbonyl C–O stretching linkages and ester linkages between lignin and hemicellulose were reduced in pretreated rice straw, suggesting the dissociation of hemicellulose and lignin networks by pretreatment [ 29 ].…”

Examination and optimization of lignocellulolytic activity of Stereum gausapatum F28 on beechwood sawdust supplemented with molasses stillage

“…The substrates with a lower amount of lignin and a higher amount of polysaccharides are more suitable for the production of hydrolytic enzymes than the substrates with a higher share of lignin such as beechwood sawdust. A study conducted by Namnuch N. et al 29 examined CMCase and xylanase production by A. flavus KUB2 on various substrates. The best activity was obtained on sugarcane bagasse (CMCase 1.04 U mL -1 and xylanase 258.38 U mL -1 ) while the lowest values were reported for production on sawdust (CMCase 0.06 U mL -1 and xylanase 14.07 U mL -1 ).…”