On the Polygalacturonase Action of Bacteria of Genus Clostridium

Abstract

A study has been done on the polygalacturonase action of Clost. acetobutylicum E4, Clost acetobutylicum K17, and Cl. butyricum W5. These organisms were useful for the fermentation retting of barks of plant fibre materials. The crude enzyme was prepared from fermentation media of Cl. acetobutylicum E4. When cations in the media were removed by Amberlite IR-120, protopectinase was also taken out of the media. The breakdown of pectic acid was determined by WILLSTÄTTER-SCHUDEL's hypoiodite method and by OSTWALD viscosimeter. When this enzyme acted on pectic acid, its viscosity decreased slightly and its reducing power increased a little. The optimum pH value for this enzymatic action was determined as 6.0 an observation of viscosity and 6.0 to 6.2 by the determination of reducing value. The enzyme was inactivated at 70° when the solution was kept on the temperature for 20 minutes. It was found that nickel, manganese and zinc ions accelerated the action of depolymeric polygalacturonase, when they were added in the concentration of 0.8 gram ion per litre. After this enzyme acted on 0.30% pectic acid solution for 7 hours to. 16 days, D-galacturonic and digalacturonic acids were detected by paper chromatography. Trigalacturoinic acid was not produced except by the enzyme of Cl. felsineum var. sikokianurm W2.
By the results of experiment in which W2 and the three bacteria were compared each other in activity of polygalacturonase, W2 bacteria produced enormously large amount of depolymeric enzyme, W5 a little, E4 and K17 slightly. But saccharifing polygalacturonase was produced a little by W2 and slightly by the other three organisms.