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Amelioration in secretion of hyperthermostable and Ca 2+ ‐independent α‐amylase of Geobacillus thermoleovorans by some polyamines and their biosynthesis inhibitor methylglyoxal‐bis‐guanylhydrazone
Author(s) -
Uma Maheswar Rao J.L.,
Satyanarayana T.
Publication year - 2004
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2004.02395.x
Subject(s) - methylglyoxal , spermidine , biochemistry , putrescine , polyamine , spermine , biosynthesis , amylase , alpha amylase , extracellular , chemistry , intracellular , enzyme , biology
Aim: Effect of polyamines and their biosynthesis inhibitors on the production of hyperthermostable and Ca 2+ ‐independent α ‐amylase by Geobacillus thermoleovorans MTCC 4220 Methods and Results: The α ‐amylase was produced in starch‐yeast extract‐tryptone (SYT) broth with different polyamines (PA) and polyamine biosynthesis inhibitors, methylglyoxal‐bis‐guanylhydrazone (MGBG) and cyclohexylammonium sulphate (CHA) at 70°C. The bacterial pellets were obtained after growing G. thermoleovorans at different temperatures, and used in determining total PA. The cell‐free culture filtrates were used in α ‐amylase assays. During growth, total polyamines in biomass increased till 2 h, and thereafter, decreased gradually. The total polyamine content was very high in the biomass cultivated at 55°C when compared with that of higher temperatures. Enzyme titre enhanced up to 70°C, and thereafter declined. Extracellular enzyme and protein levels declined in the presence of exogenously added PA. The intracellular enzyme titres, however, were higher in putrescine ( put ) and spermidine ( spd ) than in spermine ( spm ). Polyamine biosynthesis inhibitor, MGBG enhanced secretion of α ‐amylase in a laboratory fermentor as well as shake flasks, although CHA did not affect it. Conclusions: The intracellular accumulation of put in the presence of MGBG appeared to enhance synthesis and secretion of α ‐amylase. Extracellular enzyme and protein levels were low in the presence of exogenously added PA, but their intracellular levels, however, were higher in put and spd than in spm . Significance and Impact of the Study: A substantial increase in the synthesis and secretion of α ‐amylase was attained in G. thermoleovorans in the presence of polyamine biosynthesis inhibitor MGBG.