Production of Commercially Important Glucansucrase from a Newly Isolated Strain of Leuconostoc mesenteroides AA1
A Aman, S Ul Qader, S BAno, S Iqbal, A Azhar
culture optimization, dextransucrase, glucan, glucansucrase production, leuconostoc mesenteroides
A Aman, S Ul Qader, S BAno, S Iqbal, A Azhar. Production of Commercially Important Glucansucrase from a Newly Isolated Strain of Leuconostoc mesenteroides AA1. The Internet Journal of Microbiology. 2008 Volume 7 Number 1.
Glucansucrase is an industrially important extracellular enzyme produced by
Glucansucrase [18.104.22.168] commonly known as dextransucrase is a glucosyltransferase, that is responsible for glucan (dextran) synthesis from sucrose and it catalyzes the transfer of glucosyl residue from sucrose to the growing glucan polymer, liberating fructose as a byproduct (Sidebotham, 1974).
Glucansucrase and glucan have applications in various industries like pharmaceutical, food, cosmetic, agricultural, as well as in photography and mining. Specific molecular weight fractions of glucans are used in medicine, flocculation, stabilization, lyophilization, protective colloids in blood-expanders and cosmetic ingredients formulation (Kim & Day, 1994; Leather
Several species of genera
Attempts have been made to improve production of both glucan and glucansucrase by various species of
The objectives of this study were to discover and identify the most potential glucansucrase producing bacterium from locally isolated strains. Glucansucrase and glucan from
Materials and methods
Different conditions like time course, pH, substrate and temperature was optimized for maximum glucansucrase production in fermentation medium. For this purpose, culture medium was incubated for different time intervals (0-48 hours) and for the determination of glucansucrase productivity; total protein, glucansucrase activity, final pH of fermented culture broth and wet cell mass were determined.
After time course, sucrose concentration for the optimum enzyme production was varied from 0.5% to 3.5% in the culture media. For optimum temperature fermentation broths were incubated at various temperatures ranging from 15C to 45C with an increment of 5C. Where as for pH optima, pH of the culture broths was adjusted from 4.5-9.5 by the increment of 0.5 before autoclaving.
Measurements of all the experiments were determined in three independent experiments at least, each performed with three replications.
Results and discussion
In this study some of the physicochemical parameters affecting bacterial growth were controlled primarily by the changes of environment of the cultural medium such as incubation temperature, pH of medium and addition of sugar to the medium composition. These factors not only influence the cellular growth but also the enzyme production.
Taxonomic assessment of the isolated strain
Eleven bacterial isolates identified as
Selection of medium
After isolation of
Optimization of glucansucrase production
Physicochemical parameters that influence the cellular growth and enzyme production were studied including time course for enzyme production, medium composition, substrate concentration, temperature and pH.
Effect of time course on bacterial growth and enzyme production
In the first step the time course for maximum enzyme production was studied. Growth time of the bacteria in fermentation broth always plays an important role and it was observed that the cell growth of
Effect of substrate concentration
Among many factors that influence that influence the formation of bacterial enzyme, presence of particular substrate is known to be the most important factor.
Effect of temperature
Temperature may affect the metabolic pattern, nutritional requirements, and composition of bacterial cells. In addition, temperature also affects the rates of all cellular reactions. When
Different temperature maxima for glucansucrase production have been reported previously (Santos
Effect of pH
Enzyme production was also analyzed at different pH values and the optimum glucansucrase production by
The experimental data of culture conditions optimization for