Microfluidic glycosyl hydrolase screening for biomass-to-biofuel conversion.
The hydrolysis of biomass to fermentable sugars using glycosyl hydrolases such as cellulases and hemicellulases is a limiting and costly step in the conversion of biomass to biofuels. Enhancement in hydrolysis efficiency is necessary and requires improvement in both enzymes and processing strategies. Advances in both areas in turn strongly depend on the progress in developing high-throughput assays to rapidly and quantitatively screen a large number of enzymes and processing conditions. For example, the characterization of various cellodextrins and xylooligomers produced during the time course of saccharification is important in the design of suitable reactors, enzyme cocktail compositions, and biomass pretreatment schemes. We have developed a microfluidic-chip-based assay for rapid and precise characterization of glycans and xylans resulting from biomass hydrolysis. The technique enables multiplexed separation of soluble cellodextrins and xylose oligomers in around 1 min (10-fold faster than HPLC). The microfluidic device was used to elucidate the mode of action of Tm_Cel5A, a novel cellulase from hyperthermophile Thermotoga maritima . The results demonstrate that the cellulase is active at 80 °C and effectively hydrolyzes cellodextrins and ionic-liquid-pretreated switchgrass and Avicel to glucose, cellobiose, and cellotriose. The proposed microscale approach is ideal for quantitative large-scale screening of enzyme libraries for biomass hydrolysis, for development of energy feedstocks, and for polysaccharide sequencing.
Bharadwaj
Rajiv
R
Technology Division, The Joint BioEnergy Institute, Emeryville, California 94608, United States. rbharad@sandia.gov
Chen
Zhiwei
Z
Datta
Supratim
S
Holmes
Bradley M
BM
Sapra
Rajat
R
Simmons
Blake A
BA
Adams
Paul D
PD
Singh
Anup K
AK
D056804:Biofuels / Q000382:microbiology*; D018533:Biomass; D002480:Cellulase / Q000378:metabolism; D019075:Electrophoresis, Capillary; D057075:Enzyme Assays / Q000295:instrumentation*; D004795:Enzyme Stability; D052578:Ionic Liquids / Q000378:metabolism; D046210:Microfluidic Analytical Techniques; D009699:N-Glycosyl Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D009844:Oligosaccharides / Q000302:isolation & purification / Q000378:metabolism; D010944:Plants / Q000737:chemistry; D013696:Temperature; D020124:Thermotoga maritima / Q000201:enzymology; D013997:Time Factors; D014994:Xylose / Q000302:isolation & purification / Q000378:metabolism
D056804:Biofuels; D052578:Ionic Liquids; D009844:Oligosaccharides; C099423:cellohexaose; D014994:Xylose; D002480:Cellulase; D009699:N-Glycosyl Hydrolases