Fungal Pretreatment of Willow Sawdust with Abortiporus biennis for Anaerobic Digestion: Impact of an External Nitrogen Source

Abstract

Abstract:In this study the effect of nitrogen (N) supplementation in the fungal pretreatment of willow sawdust (WSD) via the white rot fungus Abortiporus biennis (A. biennis) was studied in terms of the fractionation of lignocellulosic biomass and biochemical methane potential (BMP). Thus, different external nitrogen sources (yeast extract (YE), urea (UR), and ammonium nitrate (AN)) at different ratios (N/C of 1/250 and 1/50) were added and the effect of the above parameters on the chemical composition of WSD during solid-state fermentation (SSF) experiments with A. biennis was assessed and compared to the experiment of fungal pretreatment without N supplementation (N/C was 1/500, control experiment). The results indicated that the addition of an external nitrogen source did not facilitate delignification, regardless of the type of nitrogen source and the ratio of N/C used. On the other hand, enhanced cellulose uptake was observed. Samples of the 28th day of cultivation, with and without N supplementation, were used for BMP tests, where a reduction in methane yield was observed, compared to the control experiment. In addition, a combination of fungal with alkali (20% NaOH w/w dry mass) pretreatment was performed in order to assess the effect of combined pretreatment on the lignocellulosic content and the BMP.

Enzymatic Hydrolysis of Two-way Pretreated Sawdust of <i>Eucalyptus globulus</i> and <i>Cupressus lusitanica</i>

“…It seems that pretreating with chemo-physical methods first and then with WRF like what has been done in this work than with WRF and followed by others. Alexandropoulou et al (2017) conducted a combined pretreatment with white rot fungus Abortiporus biennis and NaOH and reported a significant effect on the lignocellulotic content of the biologically pretreated willow sawdust, exhibiting a considerable loss of lignin, cellulose, and hemicellulose which were of course similar to our findings. Combined pretreatments of both white rot fungi combined with NaOH and white rot fungi combined with steam, in this experiment also similarly resulted in a significant loss of lignin and polysaccharides compared the control results.…”

“…Combination of wood rot fungal pretreatment with other pretreatment methods has been reported to increase enzymatic hydrolysis yield (Alexandropoulou et al, 2017;Martín-Sampedro et al, 2017). A mild alkali pretreatment of corn stalks with I. lacteus for 15 days significantly facilitated lignin degradation by wood rot fungi (Yu et al, 2009).…”

Does Acid Addition Improve Liquid Hot Water Pretreatment of Lignocellulosic Biomass towards Biohydrogen and Biogas Production?

“…The percentages of hydrogen and methane in the produced biogas of the BMP or BHP tests, as well as VFA (acetic, propionic, iso-butyric, butyric, iso-valeric, valeric, and caproic acid) concentrations at the end of BHP tests, were quantified via air chromatography as described in Antonopoulou et al [6] and Alexandropoulou et al [5,19]. The filter paper activity (FPU) of the commercial cellulase (Celluclast 1.5 L) was measured as presented in Antonopoulou et al [6], while scanning electron microscopy (SEM) images and attenuated total reflection (ATR) spectra were obtained as in Antonopoulou et al [15].…”

“…Anaerobic digestion (AD) for methane production and dark fermentation (DF) for hydrogen generation have been extensively studied for the exploitation of a broad variety of lignocellulosic materials [4][5][6][7]. It is reported that only 20-30% of the biomass (mainly the extractives and hemicellulose) could be converted into methane, without any treatment, during the AD process [8].…”

Sustainable Second-Generation Bioethanol Production from Enzymatically Hydrolyzed Domestic Food Waste Using Pichia anomala as Biocatalyst

“…Unlike other types of biomass, such as agricultural and forestry residues, prunings, olive mill wastes, etc. that have been used for bioethanol production [16][17][18][19][20] and other biofuels [21][22][23][24][25], DFW does not require any extensive thermal, chemical, or thermochemical pretreatment step to facilitate its subsequent bioconversion from microorganisms. This is due to its high content in readily bioconvertible compounds and nutrients that make DFW an easily fermentable substrate by various microorganisms, especially when fermentation is facilitated by enzymatic hydrolysis.…”