Synergy between cellulases and pectinases in the hydrolysis of hemp.

The impact of pectinases in the hydrolysis of fresh, steam-exploded and ensiled hemp was investigated and the synergy between cellulases, pectinases and xylanase in the hydrolysis was evaluated. About half; 59.3% and 46.1% of pectin in the steam-exploded and ensiled hemp, respectively, could be removed by a low dosage of pectinases used. Pectinases were more efficient than xylanase in the hydrolysis of fresh and ensiled hemp whereas xylanase showed higher hydrolytic efficiency than the pectinase preparation used in the hydrolysis of steam-exploded hemp. Clear synergistic action between cellulases and xylanase could be observed in the hydrolysis of steam-exploded hemp. Supplementation of pectinase resulted in clear synergism with cellulases in the hydrolysis of all hemp substrates. Highest hydrolysis yield of steam-exploded hemp was obtained in the hydrolysis with cellulases and xylanase. In the hydrolysis of ensiled hemp, the synergistic action between cellulases and pectinases was more obvious for efficient hydrolysis.

Effects of bacterial treatments on wood extractives.

Bacterial strains were isolated from spruce wood chips and their ability to reduce the content of wood extractives was studied. Strains were screened by cultivation on liquid media containing wood extractives as the major nutrient. Some bacterial species could decrease remarkably the amount of extractives in the liquid media and reduced the amount of triglycerides, steryl esters and total extractives by 100, 20 and 39%, respectively. Spruce wood chips were treated in controlled conditions with selected bacteria to test their effects on the chips. All the bacteria grew well on wood chips. The effect of bacterial metabolism on wood extractives was significant. Bacterial treatments reduced the amount of lipophilic extractives by 16-38% in 1 week of treatment and up to 67% in 2 weeks. The most efficient strain removed 90, 66 and 50% of triglycerides, steryl esters and resin acids, respectively, in 2 weeks. These results indicate that bacteria may be promising agents for the removal of extractives for improved pulping and papermaking processes.