Sunday, May 3, 2009
3-36
Bioconversion of cellulose wastes using cellulolytic biofilms
Vladimir Jirku, Jitka Hrdinova, Tereza Krulikovska, Jan Masak, and Alena Cejkova. Fermentation chemistry and bioengineering, Institute of Chemical Technology, Technicka 5, Prague 6, 166 28, Czech Republic
Celulose wastes as solid pollutants are considered in view of their lack of toxicity on the one hand and their recalcitrant nature on the other. The microbial degradation of cellulosics is frequently discussed, and the contrast between its success in handling natural cellulosic wastes versus its failure to cope with man – made refuse is described. The research carried out in the past decade has demonstrated that cellulolytic microorganisms are mostly provided with cell surface multienzyme conglomerates, which are capable of solubilizing solid cellulosic substrates. These complexes include cellulose binding and enzymatic components and serve as a substrate-targeting carrier, efficiently delivering hydrolytic component to the cellulose, if this solid substrate is physically contacted by cell surface. Therefore, a progress in establishing more efficient arrangement for technological solubilization of solid cellulosic wastes could be achieved using cellulolytic biofilms, formed by direct colonization of these wastes by cell populations of cellulolytic strains of adequate properties. In this context, the aim of presented experimental work was to characterize taxonomically not related strains to select these ones that could be engaged in above biofilm-based technology development. The capacity of respective strains to utilize different cellulosic substrates as well as to manifest cellular adherence mechanisms under the effect of physiological factors modulating the composition of cellulase system, is described. Moreover, a method enabling to imaging solid cellulose colonization (biofilm formation) was developed and found amenable to image analysis.