Role of Bacterial Growth and Their Extracellular Enzymes in Softening of Hard Root-cuttings of Jute

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The types of bacteria and their extracellular catabolic enzyme activity in a mixed bacterial culture, developed to bring about appreciable softening of hard root-cuttings of jute, were characterized. The bacterial population showed a typical diauxic growth and started secreting enzymes after 48 h of growth, which coincided with the beginning of softening process. D-glucose, a catabolite repressor, inhibited softening as well as the synthesis of bacterial extracellular proteins by 97% when added within two and a half days of incubation, later addition being ineffective. Bacterial cell-free culture supernatant, having catabolic enzyme activities, such as those of pectin transeliminase, polygalacturonase, pectin methylesterase, (jute) hemicellulase and CMCase, liberated sugars from sterile root-cuttings but was unable to bring about softening to the extent comparable to <i>in-situ</i> bacterial growth. However, when the supernatant was added along with the ruptured bacterial cell solids, the degree of softening was increased by 17%. A similar observation of partial softening was observed when the sterile cuttings were treated with a combination of proprietary fungal enzymes.</span>