Effects of wheat straw solid contents in fermentation media on utilization of soluble/insoluble nutrient, fungal growth and laccase production

Abstract

The objective of the work was to study the effect of agri-residue solid contents (2-20% w v) in fermentation medium on fungal growth, soluble and insoluble nutrient consumption and laccase production. Fungal strain and wheat straw substrate was screened for maximum laccase production. At low solid content submerged fermentation (SmF), fungus utilized mainly soluble nutrient and was unable to access the insoluble nutrient in media due to lack of contact with solid. At high solid content solid-state fermentation (SF), fungi grew on solid surface with dense and thin hyphae, utilized mainly insoluble nutrient. At medium solid content (8% w v) semi-solid fermentation (sSF), fungi grew on solid substrates with network of thick intercrossed hyphae, utilized both soluble and insoluble nutrients optimally resulting in highest fungal growth and laccase activity (~ 3.5 folds than in SmF and ~ 2.5 folds than in SF). Importance of soluble and insoluble nutrients was also established after isolation of their individual effects. Morphology of fungal growth (SEM), composition, thermal analysis (TGA/DTG) of substrates confirmed the results. sSF showed potential for the production of enzymes through utilization of agricultural residues as substrate.

Comparative study on laccase activity of white rot fungi under submerged fermentation with different lignocellulosic wastes

“…The presence of laccase, alone or together with lignin peroxidase (Lip) and manganese peroxidase (Mnp), has been demonstrated in a wide variety of white rot fungi (Mayer and Staples 2002), such as the genus Trametes, Coriolus, Pleurotus, Lentinus, Flammulina and Ganoderma (Galhaup et al 2002;Jang et al 2006;Elissetche et al 2007;Arockiasamy et al 2008;An et al 2016a, b;Guo et al 2017;Gupta and Jana 2018;Sadeghian-Abadi et al 2019;Han et al 2020). Some Trametes and Pleurotus species are efficient producers of laccase (Lorenzo et al 2002;Castanera et al 2015), such as T. versicolor, T. pubescens, and P. ostreatus (Galhaup et al 2002;Dominguez et al 2007;Park et al 2015).…”

Valorization of Lignocellulosic Wastes to Produce Phytase and Cellulolytic Enzymes from a Thermophilic Fungus, Thermoascus aurantiacus SL16W, under Semi-Solid State Fermentation

“…Accordingly, SSSF can be employed to minimize the problems associated with SSF. A previous study conducted by Gupta and Jana [ 28 ] revealed that the solid contents of agriculture residue in a fermentation medium (2‒20% w/v ) can affect the production of laccase. In terms of the wheat straw content (8% w/v ) in SSSF, the fungal strain Ganoderma lucidum could be applied as both a soluble and insoluble nutrient indicating the greatest degrees of growth and laccase activity.…”

“…On the other hand, semi-solid state fermentation (SSSF) is a type of SSF that is associated with an increase in water activity in this type of culture and provides nutrient availability for fungal growth and the control of fermentation [ 26 ]. Previous studies have reported that the enzyme contents produced under SSSF conditions were higher than those of SMF and SSF [ 27 , 28 ]. Accordingly, SSSF can potentially be used through an alternative set of conditions to address some of the drawbacks presented by SSF at high temperatures.…”

A comparative study on the laccase activity of four basidiomycete fungi with different lignocellulosic residues via solid-state fermentation

“…Recent studies have shown that lignocellulosic residues stimulate enzyme production in basidiomycetes (Pinar et al 2017;Gupta and Jana 2018;Huang et al 2019;Leite et al 2019;Sadeghian-Abadi et al 2019;Atilano-Camino et al 2020;Han et al 2020). Moreover, lignocellulosic residues are suitable for solid-state fermentation and submerged fermentation.…”