Production and Characterization of Multi-Polysaccharide Degrading Enzymes from Aspergillus aculeatus BCC199 for Saccharification of Agricultural Residues

Abstract

Enzymatic hydrolysis of lignocellulosic biomass into fermentable sugars is a key step in the conversion of agricultural by-products to biofuels and value-added chemicals. Utilization of a robust microorganism for on-site production of biomass-degrading enzymes has gained increasing interest as an economical approach for supplying enzymes to biorefinery processes. In this study, production of multi-polysaccharide-degrading enzymes from Aspergillus aculeatus BCC199 by solid-state fermentation was improved through the statistical design approach. Among the operational parameters, yeast extract and soybean meal as well as the nonionic surfactant Tween 20 and initial pH were found as key parameters for maximizing production of cellulolytic and hemicellulolytic enzymes. Under the optimized condition, the production of FPase, endoglucanase, β-glucosidase, xylanase, and β-xylosidase was achieved at 23, 663, 88, 1,633, and 90 units/g of dry substrate, respectively. The multi-enzyme extract was highly efficient in the saccharification of alkaline-pretreated rice straw, corn cob, and corn stover. In comparison with commercial cellulase preparations, the BCC199 enzyme mixture was able to produce remarkable yields of glucose and xylose, as it contained higher relative activities of β-glucosidase and core hemicellulases (xylanase and β-xylosidase). These results suggested that the crude enzyme extract from A. aculeatus BCC199 possesses balanced cellulolytic and xylanolytic activities required for the efficient saccharification of lignocellulosic biomass feedstocks, and supplementation of external β-glucosidase or xylanase was dispensable. The work thus demonstrates the high potential of A. aculeatus BCC199 as a promising producer of lignocellulose-degrading enzymes for the biomass conversion industry.

Comparison of traditional field retting and Phlebia radiata Cel 26 retting of hemp fibres for fibre-reinforced composites

“…For enzyme extraction, 4 g of bast fibres were submersed in 40 mL of 20 mM citrate buffer (pH 6.0) supplemented with 0.1% (v/v) Tween 20 and 0.25 mM dithiothreitol in a glass tube at 0 °C and shaken at 120 rpm for 1 h. For each sample, the crude enzyme extracts were concentrated until the volume was reduced to 3.0 mL (Suwannarangsee et al 2014). After concentrating, the enzyme extracts were kept at 4 °C for activity assay.…”

“…Glucanase, polygalacturonase, galactanase and xyloglucan (XG)-specific endoglucanase activities were determined by measuring formation of reducing ends. The substrates used were for glucanase 10 g/L carboxymethyl cellulose (Suwannarangsee et al 2014), for polygalacturonase 2 g/L polygalacturonic acid (Thomassen et al 2011), for galactanase 5 g/L potato galactan (Michalak et al 2012) and for xyloglucan 10 g/L tamarind xyloglucan (Benko et al 2008). Enzyme to substrate ratio of 5:1 (v/v) was used for all the enzyme activity assays.…”

Lipase-producing Filamentous Fungi from Non-dairy Creamer Industrial Waste

“…Aspergillus aculeatus is known for its ability to produce β-glucosidase (specific activity ≥180 U/mg) which is higher than other fungi [26]. Aspergillus aculeatus species is generally found in soil and the fungus can act as phosphate-solubilizing fungus [27], as well as producing several types of enzymes, such as pectinase [28], lignocellulose-degrading enzymes [29], carboxymethyl cellulase and xylanase [30]. Roy et al [31] obtained lipaseproducing Aspergillus aculeatus from soil contaminated dairy waste with optimum hydrolysis activity of 9.51 U/ ml.…”

Isolation, Identification and Screening of Antimicrobial Properties of the Marine-Derived Endophytic Fungi from Marine Brown Seaweed

“…results in producing different type of bioactive compounds. Fungus 1 was grouped with Aspergillus aculeatus (Figure 1) which is known to produce useful multipolysaccharide degrading enzymes such as βglucosidase, endoglucanase, β-xylosidase, and xylanase, and is a promising producer of lignocellulose-degrading enzymes for the biomass conversion industry (Suwannarangsee et al 2014). We did not assess enzymatic properties in our study, however "Fungus 1" could be analysed further in the future.…”