Production of Cellulase for Ethanol Fermentation from Pretreated Wheat Straw

Degradation of pretreated agroforestry residues by selected micromycetes

Nowadays, there are huge amounts of lignocellulosic materials left in agroforestry practice, which can be transformed into useful products. Biomass exploitation could be aiming not only at replacing conventional energy sources but also at preserving biodiversity and natural ecosystems. Five micromycetes were studied with goal to determine their potential to produce active cellulases as well as the ability to decompose pretreated wheat straw and oak sawdust after seven days of solid-state fermentation. Wheat straw was better lignocellulosic substrate than oak sawdust for the production of cellulases in all five micromycetes. Thus, Penicillium solitum BEOFB 1190m has shown to be the best producer of highly active forms of xylanases (7532.36 ? 89.37 U/L). The most active endo- and exocellulases (2299.70 ? 72.17 U/L and 195.66 ? 4.64 U/L, respectively) were produced by Trichoderma harzianum BEOFB 1230m, while the maximal value of ?-glucosidase activity (215.69 ? 3.13 U/L) was detected after Fusarium graminearum BEOFB 820m cultivation. T. harzianum also showed high efficiency in wheat straw cellulose and hemicellulose depolymerization (23.90% and 33.00%, respectively), which resulted in the highest dry matter loss (36.25%). The results of the study showed great potential of tested micromycetes to synthesize cellulolytic enzymes and consequently transform abundant, low-cost plant residues such as wheat straw into useful products including biofuel.

It Is the Mix that Matters: Substrate-Specific Enzyme Production from Filamentous Fungi and Bacteria Through Solid-State Fermentation

Fungi have a diverse spectrum of extracellular enzymes. In nature, extracellular enzymes primarily serve to procure nutrients for the survival and growth of the fungi. Complex polymers such as lignocellulose and starch as well as proteins and fats are broken down into their basic building blocks by extracellular enzymes such as amylases, proteases, lipases, xylanases, laccases, and many more.The abilities of these enzymes are made use of in diverse areas of industry, including food technology, textiles, and pharmaceuticals, and they have become indispensable for today's technology. Enzyme production is usually carried out using submerged fermentation (SmF). However, as part of the search for more sustainable uses of raw materials, solid-state fermentation (SSF) has become the focus of research.The rate of enzyme formation depends on different factors, for example, microorganism, temperature, or oxygen supply. However, one of the most important factors in enzyme production is the choice of substrate, which varies depending on the desired target enzyme. Substrates with proven effectiveness include wheat bran and straw, but unusual agricultural residues such as forage cactus pears and orange peels have surprisingly positive effects on enzyme formation as well.This review gives an overview of various technically relevant enzymes produced by filamentous fungi and suitable substrates for the production of the enzymes by SSF. Graphical Abstract.