Catabolic repression

In fed-batch mode residual substrate concentration may be maintained at very low levels. Ibis would reduce substrate costs, may remove catabolic repressive effects and may avoid possible toxic effects of the substrate. The fed-batch mode of operation may also avoid oxygen depletion of the culture during rapid growth. 

Transcriptionnal activity of pel genes responds differentially to catabolic repression, growth phase, temperature and nitrogen starvation. Iron limitation proved to be involved in the induction of severd of the pectinase encoding genes [7]. 

A strain Arthrobacter DBTS2 was reported to desulfurize DBT sulfone [100], It could also desulfurize DBT sulfoxide, but not DBT itself. The product of desulfurization was sulfite. The oxidation of the substrates was catabolically repressed by succinate or acetate. 

Aeromonas liquefaciens, the enzyme synthesis being catabolically repressed.264... 

No doubt the cost of xylanolytic enzymes will be one of the factors determining their application in the pulp and paper industry as well as in other areas. Economically feasible xylanase production can be achieved in paper mills employing xylanase-positive transformants of common industrially used microorganisms that are capable of utilizing inexpensive carbon sources originating there. A substantial improvement in the production of xylanolytic systems can be expeaed from mutants of non-cellulolytic microorganisms that are resistant to catabolic repression. Such mutants usually exhibit hyperproduction of extracellular enzymes. 

Thibon, C., Marullo, R, Claisse, O., Cullin, C., Dubourdieu, D., Tominaga, T. (2008b). Nitrogen catabolic repression controls the release of volatile thiols by Saccharomyces cerevisiae during wine fermentation. FEMS Yeast Research. (DOI 10 1111/j. 1567-1364.2008.00381). 

Substance Agent Action Uptake process Gene controi Catabolic repression... 

The LMW-OM (e.g., monosaccharides, amino acids, and organic acids) inhibits the activity (end-production inhibition) and represses the synthesis (catabolic repression) of ectoen-zymes in heterotrophic bacteria. 

BTX are chemically reduced compounds, thus, their biologic oxidation is thermodynamically favored (Table 7). Many biological attempts have been conducted in order to remove these volatile organic compounds from the environment. Aerobic treatments have been widely proposed for BTX elimination (Duetz et al, 1994 Haigler et al., 1992 Rozkov et al., 1998 Yerushalmi et al., 1999). Removal of BTX mixtures appeared to be favored at aerobic conditions (Deeb Alvarez-Cohen, 1999 Prenafeta-Boldu et al., 2002) however, negative effects such as inhibition or catabolic repression have also been reported at these conditions... 

Rojas-Rej6n OA, Poggi-Varaldo HM, Ramos-Valdivia AC, Martmez-Jimenez A, Cristiani-Urbina E, Martinez MDLT, Ponce-Noyola T. (2011). Production of cellulases and xylanases under catabolic repression conditions from mutant PR-22 of Cellulomonas flavigena. J Ind Microbiol Biotechnol, 38, 257-264. 

The synthesis of amylase in C. thermohydrosuljuricum 39E (ATCC 33223) was inducible and subject to cataboUc repression (2i). Catabolic repression resistant mutants were isolated which displayed improved starch metabolism features in terms of enhanced rates of growth, ethanol production and starch consumption (33). In chenxrstat cultures, both wUd type and mutant strains produced amylopuUulanase at... 

A thermophilic Streptomyces species producing a )3-l,3-D-glucanase has been grown on a chemically defined medium. The enzyme is semi-constitutive and subject to catabolic repression by metabolizable carbon substrates. Surprisingly, synthesis of the enzyme was induced by gentiobiose, which bears little resemblance to normal substrates for the enzyme. 

---