Thermostable pectate lyase from Caldicellulosiruptor kronotskyensis provides an efficient addition for plant biomass deconstruction

• Pel-863 is an alkaline and thermostable pectate lyase of C. kronotskyensis.
• Pel-863 is encoded by gene cluster for pectic polysaccharide metabolism.
• Pel-863 requires divalent cation as cofactor which located in a spatial cleft.
• Pel-863 degrades (un-)methylated pectin and pectic biomass by endo-cleaving action.
• Pel-863 pre-digestion was effective for degumming and pectic biomass degradation.

To understand the enzymological basis for extremely thermophilic, biomass-degrading genus Caldicellulosiruptor metabolize pectin, a thermostable pectate lyase Pel-863 encoded by a gene cluster for hexose-containing polysaccharide metabolism in genome of C. kronotskyensis was studied. The pectate lyase of Caldicellulosiruptor was highly conserved and the representative Pel-863 was biochemically characterized, and the application for pectin containing biomass degradation was also studied. Pel-863 exhibited an optimal activity at 70 °C and pH 9.0 with Ca2+ as cofactor. It degraded polygalacturonic acid (PGA), methylated pectin and pectic biomass through endo-cleaving action. The respective Vmax and Km for Pel-863 were 172.8 U/mg and 0.60 g/L on PGA. FTIR and SEM analysis indicated that Pel-863 could remove most of pectin in hemp fiber with less damage compared to alkaline degumming. In addition, pre-digestion with Pel-863 improved glucose and xylose yield by 14.2% and 311.6% respectively for corn stalk, 6.5% and 55% for rice stalk compared with sole action of Novozymes Cellic CTec2.

Figure optionsDownload as PowerPoint slide