title: Enhanced enzymatic hydrolysis of rice straw by removal of phenolic compounds using a novel laccase from yeast Yarrowia lipolytica.
abstract: An extracellular laccase-producing yeast was isolated from soil and identified as Yarrowia lipolytica by its morphology and by comparison of its internal transcribed spacer rDNA gene sequence. Extracellular laccase (YlLac) from Y. lipolytica was purified to homogeneity by anion-exchange and gel filtration chromatography. YlLac is a monomeric glycoprotein with 14% carbohydrate content and a molecular mass of 67kDa. It showed a higher catalytic efficiency towards 2,2'-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (k(cat)/K(m)=19.3s(-1)μM(-1)) and 2,6-dimethoxyphenol (k(cat)/K(m)=13s(-1)μM(-1)) than any other reported laccase. This enzyme was able to oxidize phenolic compounds present in pretreated rice straw. Several parameters (temperature, enzyme concentration, and mediator compounds) to enhance removal of phenolic compounds from pretreated rice straw were optimized using response surface methodology. The use of YlLac for the removal of cellulase inhibitory compounds from biomass slurries was found to be a promising approach for improving the efficiency of biorefineries.
authors.affiliation: Institute of SK-KU Biomaterials, Konkuk University, Seoul 143-701, Republic of Korea.
authors.forename: Kyoung-Mi
authors.initials: KM
authors.lastname: Lee
authors.forename: Dayanand
authors.initials: D
authors.lastname: Kalyani
authors.forename: Manish Kumar
authors.initials: MK
authors.lastname: Tiwari
authors.forename: Tae-Su
authors.initials: TS
authors.lastname: Kim
authors.forename: Saurabh Sudha
authors.initials: SS
authors.lastname: Dhiman
authors.forename: Jung-Kul
authors.initials: JK
authors.lastname: Lee
authors.forename: In-Won
authors.initials: IW
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D001673:Biodegradation, Environmental / Q000187:drug effects; D050260:Carbohydrate Metabolism / Q000187:drug effects; D002480:Cellulase / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019143:Evolution, Molecular; D006868:Hydrolysis / Q000187:drug effects; D007477:Ions; D007700:Kinetics; D042845:Laccase / Q000302:isolation & purification / Q000378:metabolism*; D008670:Metals / Q000494:pharmacology; D008969:Molecular Sequence Data; D012275:Oryza / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D010636:Phenols / Q000302:isolation & purification*; D010802:Phylogeny; D015203:Reproducibility of Results; D013379:Substrate Specificity / Q000187:drug effects; D014866:Waste Products / Q000032:analysis*; D025062:Yarrowia / Q000201:enzymology* / Q000302:isolation & purification
chemical_list: D004791:Enzyme Inhibitors; D007477:Ions; D008670:Metals; D010455:Peptides; D010636:Phenols; D014866:Waste Products; D042845:Laccase; D002480:Cellulase