Description:
Cyclodextrin glycosyl transferase (CGTase; EC 2.4.1.19) is the enzyme that
converts starch into cyclodextrins (CD’s) which are closed-ring structures having
six or more glucose units joined by means of α-1, 4 glucosidic bonds. CGTases are
classified in the α-amylase family and are known to catalyze four different
transferase reactions: cyclisation, coupling, disproportionation, and hydrolysis
.Three major types of Cyclodextrins are produced by CGTases depending on
number of glucose units, α – CD, β- CD and γ- CD. CGTase is used for industrial
production of cyclodextrin and for biotransformation. Cyclodextrins have a variety
of applications in food, pharmaceutical and cosmetic industry. Cyclodextrins are
used as drug carriers and tabletting vehicles.
It is evident from the above mentioned applications that CGTase enzyme is
industrially a very important enzyme because of its application in production of
CD’s. However, its application is still significantly limited because of its low yield
and extravagant price. CGTase from alkaliphilic Bacillus sp. overcame all these
problems and lead to mass production of α – CD, β- CD and γ- CD .Since then it is
known that alkaliphiles are candidate organisms for CGTase production.
In India, Lonar Lake (Buldhana Dist., Maharashtra State) is a well known alkaline
lake formed by meteorite impact in basalt. The cultivable bacterial diversity of
Lonar lake and screening of organisms for industrially important compounds with
biotechnological applications (PHA, EPS, proteases) has been studied previously
but there is no report on the occurrence of CGTase in organisms isolated from
Lonar Lake. Thus studies on alkaliphilic bacteria from Lonar Lake for production
of CGTase may pave way for discovery of this extremozyme with huge
biotechnological potential and application for production of CD’s.