Fractional factorial designs applied to enzymatic sugar beet pulps pressing improvement

The effects of several plant cell wall polysaccharides degrading enzymes on sugar beet pulps pressing were studied. Study was carried out using three two level fractional factorial experiment designs. With only 36 experiments , the effects of the presence of pectin methylesterase, pectin lyase, polyg alacturonase, cellulase, arabinase, xylanase and two rhamnogalacturonases o n pressing were examined. Pectin lyase, pectin methylesterase and cellulase had a negative effect and caused the decrease of sugar beet pulp pressabil ity. On the contrary, the presence of polygalacturonase, arabinase and xyla nase increased pressing efficiency. When increasing enzymes concentrations, these effects varied and positive interactions between xylanase and polyga lacturonase appeared. The presence of each of the two rhamnogalacturonases improved pressability despite their antagonistic effects. These enzymes had a complex effect and strongly interacted with polygalacturonase, arabinase and xylanase.