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

Abstract

Agricultural wastes are lignocellulosic biomasses that contain high mineral and nutrient contents. This waste can be used as a raw material in industrial enzyme production by microbial fermentation. Phytase is an important enzyme used in animal feed to enhance the amount of phosphorus available for the growth and overall health improvement of monogastric animals. Fungi offer high potential as an effective source in the production of various extracellular enzymes. In this study, the production of lignocellulolytic enzymes (endoglucanase and xylanase) and phytase by a thermophilic fungus, namely Thermoascus aurantiacus strain SL16W, was evaluated using sixteen different Thai agricultural forms of waste under conditions of high temperature (45 °C). Semi-solid state fermentation was used in the production experiments. The results of this study reveal that the highest phytase activity (58.6 U/g substrate) was found in rice bran, whereas the highest degrees of activity of endoglucanase and xylanase were observed in wheat bran and red tea leaves at 19 and 162 U/g substrate, respectively. Consequently, the optimal conditions for phytase production of this fungus using rice bran were investigated. The results indicate that the highest phytase yield (58.6 to 84.1 U/g substrate) was observed in rice bran containing 0.5% ammonium sulfate as a nitrogen source with 10 discs of inoculum size at a cultivation period of 9 days at 45 °C and moisture content of 95%. Notably, the phytase yield increased by 1.71-fold, while endoglucanase and xylanase were also increased by 1.69- and 1.12-fold, respectively. Furthermore, the crude enzyme obtained from the optimal condition was extracted. The crude enzyme extract was then separately added to red tea leaves, rice straw, corncobs, palm residue, and peanut husks. Subsequently, total reducing sugar and phosphorus contents were determined. The results indicate that the highest level of reducing sugar (122.6 mg/L) and phosphorus content (452.6 mg/L) (p < 0.05) were obtained in palm residue at 36 and 48 h, respectively, after the addition of the crude enzyme extract. This study has provided valuable information on a potentially eco-friendly way to valorize agricultural waste into value-added products as industrial enzymes.

Difference of microbial community and gene composition with saccharification function between Chinese nongxiangxing daqu and jiangxiangxing daqu

“…4). Currently, some microorganisms such as Aspergillus and Thermoascus with cellulolytic enzyme‐producing ability have been used for disposal of Baijiu distiller′s grains 37,38 . However, few published articles have reported that these unculturable microorganisms such as Byssochlamys and Rasamsonia could product cellulolytic or hemicellulolytic enzymes as well.…”

“…Currently, some microorganisms such as Aspergillus and Thermoascus with cellulolytic enzyme-producing ability have been used for disposal of Baijiu distiller 0 s grains. 37,38 However, few published articles have reported that these unculturable microorganisms such as Byssochlamys and Rasamsonia could product cellulolytic or hemicellulolytic enzymes as well. Therefore, we recommend that more emphasis should be placed on degradation and transformation of cellulose and hemicellulose in the Baijiu industry, in which related strains are required to participate.…”

Impact of Climate Change on Agriculture Production in District Kinnaur, Himachal Pradesh

“…The statistical analysis for optimization of incubation time showed p-value is 0.000, the experiment was significant at 95 percent confidence level. Tanruean et al (2021) reported that Thermoascus aurantiacus strain SL16W showed maximum phytase production at 12 days of fermentation. Alves et al (2016) reported similar results, using Muscodor sp.…”

Using Green Waste as Substrate to Produce Biostimulant and Biopesticide Products Through Solid-State Fermentation

“…As it was mentioned before, no evidence of using grass and pruning waste through solid-state fermentation was found. However, other lignocellulosic wastes especially agricultural wastes have been successfully used as substrate in solidstate fermentation (Marín et al, 2019;Tanruean et al, 2021;Wang et al, 2019). Moreover, regarding the low biological activity of the grass and the future scale-up of the process, the mixture probably provides more advantages in this case.…”