Chastain, Jane L.2021-03-032021-03-031983http://hdl.handle.net/10919/102592In the course of studies on degradation of dietary fiber by the human colon bacteria, a number of Bacteroides strains from the human colon have been found to degrade polygalacturonic acid and/or pectin. Four of these strains were examined for presence of polygalacturonate lyase (PGAL). The Bacteroides strains studied synthesized inducible, cell-associated PGALs when the bacteria were grown on media containing polygalacturonic acid or on peanut cell wall (a prototype dietary fiber with a uronide content of 14.0%) as the sole carbon source. No PGAL activity could be detected in cultures grown on media containing glucose or D-galacturonate. The PGALs produced by the four Bacteroides strains had properties similar to other bacterial PGALs: An alkaline pH optima (8.5), stimulation of activity by calcium ions. complete inhibition by ethylenediaminetetraacetic acid (EDTA), preference for polygalacturonic acid as a substrate over pectin, and accumulation of unsaturated products which absorb at 235 nm. The Bacteroides PGALs catalyzed partial degradation of the uronides of peanut cell wall substrate, but at a slower rate compared to their action on polygalacturonic acid substrate.v, 60 leavesapplication/pdfenIn CopyrightLD5655.V855 1983.C427BacteroidesThesis