Influence of cellulases on indigo backstaining

We have found that increasing concentrations of fungal cellulases on a fabric decrease indigo staining levels. Deletion of the cellulose binding domains (CBD) from either bacterial or fungal cellulases decreases indigo staining levels and generally causes less backstaining than the entire enzyme. Increasing the concentration of cellulases with a CBD of family I on fabric decreases indigo staining, whereas increasing the concentration of cellulase with a CBD of family II has no effect on staining. After-washing experiments of indigo-stained cotton fabrics show that it is easier to remove indigo adsorbed on cellulase adsorbed onto cotton than indigo directly adsorbed onto cotton

Indigo backstaining during cellulase washing

We have attempted to understand the mechanisms of indigo backstaining during enzyme stone washing by separately analyzing dye staining levels on different cotton surfaces during the process. The high ability of the cellulase enzyme protein to bind to cotton cellulose is the major cause of backstaining. Further studies of commercial cellulases show that the pH of maximum cellulase activity may not be the same pH of maximum of cellulase binding capacity to the substrate, and also that indigo dyes have completely different affinities for cellulase proteins from different fungal origins

Screening for conditions of enhanced production of a recombinant beta-glucanase secreted into the medium by Escherichia coli

Spexard M, Beshay U, Risse JM, Miksch G, Flaschel E. Screening for conditions of enhanced production of a recombinant beta-glucanase secreted into the medium by Escherichia coli. BIOTECHNOLOGY LETTERS. 2010;32(2):243-248.The extracellular production of a hybrid bacterial beta-glucanase using Escherichia coli was studied by using combinations of promoters of varying strength for both a beta-glucanase as the target protein and the Kil protein as the releasing factor. Four strains with different combinations of promoter strengths were cultivated in shake-flasks on four different media to assess the cross-influence of promoter and medium in a general manner. Promoters were taken from natural as well as synthetic sequences known to exhibit either weak or strong promoter strength. By far the highest extracellular glucanase activity (> 200 U ml(-1)) was achieved when a strain harbouring the kil gene under control of a strong synthetic stationary-phase promoter and the glucanase gene under control of a strong synthetic constitutive promoter was cultivated on a complex medium mainly composed of casein peptone, yeast extract, and glycerol