Highly Potent Saccharification of Arthrospira maxima Glycogen by Fungal Amylolytic Enzyme from Trichoderma Species J113

Abstract

Hydrolytic enzymes from fungi have been widely used to convert complex plant-based substrates into more suitable fermentation substrates. Recently, photosynthetic microorganisms, particularly cyanobacteria, are garnering interest as an alternative to plant-based biomass for renewable energy production. Our goal was to identify a new source of enzymes with improved amylolytic efficiency in cyanobacterial glycogen hydrolysis. We isolated a new Trichoderma species J113 strain from the coastal terrains of Korea and determined that the fungus has a high amylolytic enzyme activity. We cultured the fungus on wheat bran to stimulate enzyme production, and the crude extract was subsequently purified through filtrations, precipitation, and chromatography. We observed that J113 enzyme consists of two putative major amylases: Ayt40 and Ayt70, that were determined as an alpha-amylase and a gluco-amylase, respectively. While these two amylases exhibited different pH and temperature requirements for optimum performance, collectively J113 enzyme showed the highest activity at pH 4 and 60 A degrees C. In addition, we were able to drastically enhance the amylolytic capacity of Ayt70 gluco-amylase by 291 % with 5 mM Mn2+ amendment. Significantly, J113 enzyme converted 20 g/L (10 g total carbohydrate) of Arthrospira maxima to 8.3 g/L of reducing sugar with Mn2+ compared to only 5.1 g/L without Mn2+ in 240 min of reaction. Our study demonstrated that the newly isolated amylase extract from Trichoderma species J113 has the potential to be further optimized for efficient large-scale saccharification of algal glycogen for bioethanol production.