Synergy of crude enzyme cocktail from cold-adapted Cladosporium cladosporioides Ch2-2 with commercial xylanase achieving high sugars yield at low cost

Abstract

BackgroundThe efficiency and cost of current lignocellulosic enzymes still limit the large-scale production of cellulosic ethanol in industry. Residual lignin after pretreatment severely depresses the activity of polysaccharide hydrolases and the h ydrolysis of holocellulose. If we include in hydrolase mixture construction the ligninase involved in lignin degradation, which mainly includes laccase, manganese peroxidases (MnP) and lignin peroxidase (LiP), it is feasible that this could greatly improve the fermentable sugars yield.ResultsThe psychrophilic lignocellulosic enzymes system of Cladosporium cladosporioides Ch2-2 including ligninase and polysaccharide hydrolases was suitable for selective delignification and efficient saccharification of biomass with wide thermal adaptability. The purified laccase was optimally active at 15°C and pH 3.5, exhibiting high thermostability over a broad range of temperatures (between 4 and 40°C). In addition, manganese-independent peroxidase (MIP), a special type of ligninase with the capacity to oxidize dimethyl phthalate (DMP) in the absence of H2O2 and Mn2+, was optimally active at 20°C and pH 2.5, exhibiting high thermostability over a broad range of temperatures (4 and 28°C), while depressed completely by Fe2+ and essentially unaffected by EDTA. Synergy between Ch2-2 crude enzymes and commercial xylanase obviously enhanced biomass hydrolysis, which could take the place of expensive commercial cellulase mixture. The maximum value of synergistic degree reached 4.7 at 28°C, resulting in 10.1 mg/mL reducing sugars.ConclusionsThe psychrophilic enzymes system of C. cladosporioides Ch2-2 with a different synergistic mechanism has huge potential for the enhancement of biomass hydrolysis at mesophilic and low temperatures. The application scope of the lignocellulosic enzyme cocktail could be greatly enlarged by optimizing the operation conditions specific to the characteristics of ligninase.

Two decades of warming increases diversity of a potentially lignolytic bacterial community

“…We also included other papers that were not included in this search but were already familiar to us. The genera appearing in this search but not found in our dataset were Aeromonas (Gupta et al, 2001 ), Aneurinibacillus (Chandra et al, 2007 ), Azotobacter (Morii et al, 1995 ), Cladosporium (Ji et al, 2014 ), Desulfovibrio (Kim et al, 2009 ), Enterobacter (DeAngelis et al, 2013 ), Kocuria (Parshetti et al, 2011 ), Microbulbifer, Sagittula (González et al, 1996 ; Chen et al, 1997 ) Micrococcus (Taylor et al, 2012 ), Pantoea (Xiong et al, 2014 ), Thaurea (Kim et al, 2009 ), Thermobifida (Chen et al, 2013 ), and Xanthomonas (Odier and Monties, 1978 ).…”

A novel bifunctional GH51 exo-α-l-arabinofuranosidase/endo-xylanase from Alicyclobacillus sp. A4 with significant biomass-degrading capacity

“…Synergy of hydrolytic enzymes has been extensively studied in prior studies [ 39 – 41 ], which is a useful way to improve sugar yield at low cost. When Ac-Abf51A was incubated in combination with endo-xylanase XynBE18 sequentially or simultaneously to degrade wheat arabinoxylan, more reducing sugars were released.…”

Lipopeptide produced from Bacillus sp. W112 improves the hydrolysis of lignocellulose by specifically reducing non-productive binding of cellulases with and without CBMs

“…The FPA and activities of CMCase, pNPCase, pNPGase were assayed as described elsewhere [ 43 , 64 ]. The protein concentration measured directly in supernatant does not represent actual enzyme concentration because of the interference of lipopeptide.…”

“…Substrate (2% of DA-GJG with different lignin contents or Avicel and lignin), CEL and lipopeptide (no addition in control group) were mixed in 1 mL of sodium acetate buffer (50 mM, pH 5.0) and incubated at 0 °C, 200 rpm for 1 h. The activities of CMCase, pNPCase, pNPGase and FPA in the supernatant were measured after incubation [ 43 , 64 ]. The activities in the system without any substrates were designated as 100%.…”