Cellulase recycling in biorefineriesis : is it possible?

On a near future, bio-based economy will assume a key role in our lives. Lignocellulosic materials (e.g., agroforestry residues, industrial/solid wastes) represent a cheaper and environmentally friendly option to fossil fuels. Indeed, following suitable processing, they can be metabolized by different microorganisms to produce a wide range of compounds currently obtained by chemical synthesis. However, due to the recalcitrant nature of these materials, they cannot be directly used by microorganisms, the conversion of polysaccharides into simpler sugars being thus required. This conversion, which is usually undertaken enzymatically, represents a significant part on the final cost of the process. This fact has driven intense efforts on the reduction of the enzyme cost following different strategies. Here, we describe the fundamentals of the enzyme recycling technology, more specifically, cellulase recycling. We focus on the main strategies available for the recovery of both the liquid- and solid-bound enzyme fractions and discuss the relevant operational parameters (e.g., composition, temperature, additives, and pH). Although the efforts from the industry and enzyme suppliers are primarily oriented toward the development of enzyme cocktails able to quickly and effectively process biomass, it seems clear by now that enzyme recycling is technically possible.Financial support from FEDER and Fundação para a Ciência e a Tecnologia (FCT): GlycoCBMs Project PTDC/AGR-FOR/3090/2012–FCOMP-01-0124- FEDER-027948 and Strategic Project PEst-OE/EQB/LA0023/2013, Project BBioInd-Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028 Cofunded by the Programa Operacional Regional do Norte (ON.2–O Novo Norte), QREN, FEDER and the PhD grant to DG (SFRH/BD/88623/ 2012) and ACR (SFRH/BD/89547/2012)

Characterization of Paenibacillus curdlanolyticus B-6 Xyn10D, a Xylanase That Contains a Family 3 Carbohydrate-Binding Module ▿ †

Paenibacillus curdlanolyticus B-6 Xyn10D is a xylanase containing a family 3 carbohydrate-binding module (CBM3). Biochemical analyses using recombinant proteins derived from Xyn10D suggested that the CBM3 polypeptide has an affinity for cellulose and xylan and that CBM3 in Xyn10D is important for hydrolysis of insoluble arabinoxylan and natural biomass

Lignocellulosic waste material as substrate for Avicelase production by a new strain of Paenibacillus chitinolyticus CKS1

A novel strain of Paenibacillus chitinolyticus CKS1 was isolated from forest soil and identified as a potent cellulase producer. The strain was able to grow on various commercial substrates including microcrystalline cellulose (Avicel), carboxymethylcellulose (CMC), and cellobiose but also on lignocellulosic waste material such as medicinal herbs waste and sawdust. On all these substrates the strain produced cellulase composed of two subunits (similar to 70 and similar to 45 kDa) that was active on CMC, Avicel and filter paper. The maximal Avicelase activity (1.94 U/ml) was reached in a medium that contained 0.1% (w/v) of medicinal herbs waste, 3 g l(-1) of yeast extract and 5.0 g l(-1) of casein hydrolysate in 0.1 M phosphate buffer pH 7, after 48 h of incubation at 30 degrees C. The Avicelase performed optimally at 80 degrees C and at pH 4.8. Addition of K+ increased the Avicelase activity almost three fold and the enzyme retained 48.39% of the initial activity after 60 min. The product of Avicel and CMC hydrolysis was glucose with traces of other soluble sugars, indicating that the crude cellulase produced on waste material using the novel P. chitinolyticus strain CKS 1 could be used in eco-friendly processes of cellulose bioconversion, such as enzymatic saccharification of lignocellulosic materials in processes performed under acidophilic conditions and high temperatures