Characterization of the cellulolytic activity of a Bacillus isolate

Abstract

A group I Bacillus strain, DLG, was isolated and characterized as being most closely related to Bacillus subtilis. When grown on any of a variety of sugars, the culture supernatant of this isolate was found to possess cellulolytic activity, as demonstrated by degradation of trinitrophenyl-carboxymethyl cellulose. Growth in medium containing cellobiose or glucose resulted in the greatest production of cellulolytic activity. The cellulolytic activity was not produced until the stationary phase of growth, and the addition of glucose or cellobiose to a culture in this phase had no apparent effect on enzyme production. Fractionation of the culture supernatant showed that the molecular weight of the enzymatic activity was <100,000. Maximum cellulolytic activity in assays was observed at pH 4.8 and at 58°C, although maximum thermal stability of the activity was observed only up to 45 to 50°C. Neither glucose nor cellobiose inhibited enzymatic activity. Kinetic experiments suggested that more than one enzyme was acting upon trinitrophenyl-carboxymethyl cellulose. Exocellular protein produced by this Bacillus isolate showed roughly onefifth the cellulolytic activity displayed by Trichoderma reesei C30 on noncrystalline cellulosic substrates. In contrast to T. reesei cellulase, the Bacillus enzymatic activity showed no ability to degrade crystalline forms of cellulose, nor was cellobiase activity detectable.

Industrial waste based compost as a source of novel cellulolytic strains and enzymes

“…Bacillus spp. have been widely reported as cellulolytic microorganisms (Robson & Chambliss, 1984;Fukumori et al, 1985;Kawai et al, 1988;Abou-Taleb et al, 2009). Bacillus subtilis, B. megaterium and B. amyoliquefaciens from soil, Bacillus pumilis from rot biomass, Paenibacillus polymyxa and Brevibacillus sp.…”

“…Among the manuscripts so far reported on characterization of native cellulases from Bacillus spp. (Robson & Chambliss, 1984;Fukumori et al, 1985;Kawai et al, 1988;Singh et al, 2004;Kotchoni et al, 2006;Lee et al, 2008;Liang et al, 2009;Afzal et al, 2010;Annamalai et al, 2011;Zhu et al, 2011;Rawat & Tewari, 2012), only one regards a strain of B. amyoliquefaciens (Lee et al, 2008).…”

“…In B. amyloliquefaciens B31C, glucose causes a decrease of cellulase production suggesting its role of catabolite repressor. Cellobiose and glucose substrates have been shown to be inducers of cellulase production for some cellulolytic microbes (Robson & Chambliss, 1984;Paul & Varma, 1990), whilst glucose has been also reported as a catabolite repressor (Abou-Taleb et al, 2009).…”

Some factors affecting endo‐β‐1,4‐glucanase production by two Bacillus strains isolated from Zimbabwean hot springs

“…Production of endo-@-I ,4-glucanase by strain CH43 is induced because it only produced the enzyme when grown on medium containing CMC as the carbon source but not on simple sugars as carbon sources. ROBSON and CHAMBLISS (1984), DHILLON et al ( 1985). AU and CHAN (1986), PAUL and VARMA (1990) reported the production of endo-@-1 ,Cglucanase by Bacillus strains grown on simple sugars as carbon sources.…”

“…The Bacillus group has been shown by some workers to produce the endo-b-1,4-glucanase (an endocellulase) only and does not produce the complete cellulase enzyme complex (Au and CHAIN 1986, 1987, C H A N~~~A U 1987, OKISHI et al 1990). While cellulase production by Bacillus strains is interesting due to the wide variety of characteristics and regulatory mechanisms of the enzyme (ROBSON and CHAMBLISS 1984), there are very few physiological studies that have been done on Bacillus cellulase system CHAN 1986, CHAN and. Thus although it is known that the endo-/3-1,4-glucanase is produced by some Bacillus strains constitutively in the log phase using simple sugars as the carbon source there are no reports of enzyme production during continuous cultivation of these strains, to the best of our knowledge.…”