Enhanced Endoglucanase Production by Bacillus aerius on Mixed Lignocellulosic Substrates

Abstract

Selected carbon sources including soluble carboxymethyl cellulose (CMC), insoluble microcrystalline cellulose (MCC), and single (SS)/mixed lignocellulosic substrates (MS), were evaluated for endoglucanase production by B. aerius S5.2. The lignocellulosic substrates of oil palm empty fruit bunch (EFB), oil palm frond (OPF), rice husk (RH), and their mixture (MS) supported growth of the strain better than CMC and MCC. The maximum endoglucanase activity on MS was 7.3-, 2.6-, 1.7-, and 1.2-fold higher than those recorded on MCC, CMC, EFB/OPF, and RH, respectively. While the reducing sugar concentration of the CMC medium was comparable to that of the EFB and MS media, wide variability was observed in the reducing sugar concentrations among the lignocellulosic substrates. Extremely low levels of sugar were detected in the MCC medium, reflecting its poor digestibility and hence unsuitability for growth and endoglucanase production. Endoglucanase production was predominantly extracellular when the strain was grown on CMC and MS. After seven days of fermentation, there was an approximately 25% reduction in MS dry weight. These findings show that the use of mixed lignocellulosics could potentially reduce the cost of cellulase production. Certain novel aspects of the cellulase system of B. aerius are reported in this study.

Mixed Feedstock Approach to Lignocellulosic Ethanol Production—Prospects and Limitations

“…High ethanol yield obtained in the mixture without additional nitrogen supplementation [37] Oil palm and rice residues Endoglucanase production Endoglucanase production was one-to sevenfolds higher on mixed substrate than on single pure cellulosic and lignocellulosic substrates [57] Wheat straw and hybrid poplar Fermentable sugar production…”

Assessment of the Effect of Easily-metabolised Carbon Supplements on Xylanase Production by Newly Isolated Trichoderma asperellum USM SD4 Cultivated on Oil Palm Empty Fruit Bunches

“…As a consequence of the remarkable improvement in enzyme yields by mixture of some lignocellulosic substrates, recent studies have focused on exploiting the synergistic effect of mixing several other substrates to achieve higher yields of hydrolytic enzymes. Rice straw and wheat bran (Shenef et al 2010), OPEFB and rice husk (Oke et al 2016), and several other combinations (Pathak et al 2014) have been mixed, leading to a higher enzyme titre. Given the inductive abilities respectively of simple easily-metabolised sugars (monosaccharides, disaccharides and less complex polysaccharides) and lignocellulosic substrates on xylanase production, it is presumed that the use of a mixture of these respective substrates could lead accordingly to a more efficient xylanase production.…”

Cellulase production by co-culture of Bacillus licheniformis and B. paralicheniformis over monocultures on microcrystalline cellulose and chicken manure-supplemented rice bran media

“…Likewise, CMCase (0.21 U/mL) and FPase (0.13 U/mL) activity was recorded by thermophilic Bacillus subtilis BHUJPV-H12 grown on CMC and filter paper substrate (Singh et al 2019). In another study, a lower CMCase activity 0.108 U/mL from B. aureus was observed on MCC (Oke et al 2016). In the current study, better results were found in terms of the enzyme activities.…”