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Bangladesh Journal of Biochemistry, Vol. 3, No. 1, 1-10, June
1997
INDUCTION
OF CELLULASE-FREE XYLANASE IN THERMOPHILIC FUNGUS THERMOMYCES LANUGINOSUS
RT9
M. Mohiuddin BHUIYAN,
Donald J. GOMES and M. Mozammel HOQ
Department of Microbiology, University of Dhaka, Dhaka, Dhaka-1000, Bangladesh
(Received 21 May, 1997)
Abstract
The induction of cellulase-free xylanase of thermomyces lanuginosus
RT9 was studied. The most potent inducer of the enzyme was birch-wood
xylan, while other readily metabolized carbon sources like arabinose,
galactose, glucose and glycerol did not induce synthesis. Cellulase
synthesis was not induced by any of these substrates. Similar banding
pattern was observed when the culture supernatants from T. lanuginosus
RT9 grown on the two inducers (xylan and Xylose) where analyzed
by SDS –PAGE. The fungus displayed optimum growth and enzyme production
on xylan and xylose at concentration of 4% and 2%, respectively. The
optimum temperature and initial culture pH for xylanase synthesis
were 47ºC and 6.0, respectively. The rate of xylanase
synthesis increased with the increase of initial mycelial concentration,
and the rate of synthesis by pre-induced mycelia was always higher
than that by repressed mycelia. Transfer of pre-induced mycelia into
inducer-free basal medium or glucose medium caused de-induction of
xylanase synthesis
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Journal of Biochemistry, Vol. 3, No. 1, 11-18,
June 1997
DEAMIDATION OF FOOD
PROTEIN BY PARTIALLY PURIFIED DEAMIDASE FROM GERMINATING WHEAT SEED
Ranajit Kumar SHAHA,
Department of Biochemistry, University of Rajshahi, Rajshahi- 6205, Bangladesh.
Naotoshi MATSUDOKMI, Akio KATO
Department of Biological Chemistry, Yamaguchi University, Japan.
(Received 25
June, 1997)
Abstract
A new method for the deamidation of seed storage proteins using partially
purified deamidase from germinating wheat seed is described and proposed
as a desirable method for food protein processing. A considerable
amount of ammonia was detected by the deamidase treatment of soy protein
(7S and 11S globulin) in phosphate-citrate buffer, pH 6.0 compared
to ovalbumin and lysozyme. The optimal pH of deamidation was around
7.0 and the optimal temperature was 31°C. The deamidation of proteins
linearly increased in proportion to deamidase concentration. Deamidation
percentages of ovalbumin, lysozyme, 7S globulin and 11S globulin were
8.0, 8.2, 29.0 and 30.0, respectively while no proteolysis was observed
under these conditions. Both emulsifying and foaming properties of
plant proteins were improved by treatment with partially purified
wheat deamidase. This property can be profitably exploited in food
technology..
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Bangladesh
Journal of Biochemistry, Vol. 2, No. 1, -19-29, June
1997
SOME METHODS FOR THE STABILIZATION OF RICE BRAN OIL
M. Maskud ALI, Nurul ABSAR, M. SHAHJAHAN, M. G. HUSSAIN
and Parvez HASSAN
Department of Biochemistry, University of Rajshahi, Rajshahi-6205, Banglsdesh.
(Received 29 June, 1997)
Abstract
Milling (Auto Rice Mills) of rice (Oryza sativa L.) separates the
germ from the outer coating commonly known as ‘Rice Bran’. Rice bran
contains considerable amount of oil and has a good potential as a
contributor to world oil supply. However, it is hardly considered
is an edible oil raw material source in our country, particularly
for the instability of the oil during storage. Several studies have
been conducted for stabilizing of rice bran using dry and moist heat
treatments and chemical treatment. Of them the chemical method for
stabilization of rice bran (based on the principle of reducing lipase
activity by lowering the pH) has proved to be most successful. The
changes in physico-chemical characteristics of the stabilized and
non-stabilized rice bran oils were also studied by conventional methods
and the results revealed that the stabilized bran can be unique industrial
potential as an edible oil source.
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Journal of Biochemistry, Vol. 3, No. 1, 31-34,
June 1997
EFFECT
OF ANTIMONY ON LIVER AND KIDNEY FUNCTIONS OF GUINEA-PIG
Nurul ABSAR, Mir
MISBAHUDDIN and Shahriar ZAMAN
Department of Biochemistry, University of Rajshahi, Rajshahi
(Received 16 October
1996)
Abstract
The effects of pentavalent antimony [Sb(v)] on tissues, specially
liver and kidney, of guinea-pigs were investigated. The activities
of serum ALT, AST and alkaline phosphatase were markedly affected
by pentavalent antimony in the form of sodium stibogluconate (SSG)
and after 20 days of injection of 10 mg Sb(v)/kg body weight/day,
the activities declined by 28.6%, 38.6% and 31.5%, while with the
administration of further dosages of SSG, e.g. 40 mg/kg/day, the activities
decreased by 36.9%, 50.7%, and 42.4%, respectively. The effect of
SSG was much more pronounced with the administration of first dosage
regimen of SSG. The level of serum creatinine was also found to be
decreased significantly while levels of total protein, albumin and
globulin decreased moderately.
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Journal of Biochemistry, Vol. 3, No. 1, 35-41, June 1996
OPTIMISATION
OF GROWTH CONDITION OF SACCHAROMYCES CERVISIAE DSM 1848 FOR THE
PRODUCTION OF EXTRACELLULAR LIPASES
Saqib H.SHIRAZI,
Sabita R. RAHMAN and M. Majibur Rahman.
Department of Microbiology, University of Dhaka, Dhaka-1000, Bangladesh.
(Received 8 April,
1997)
Abstract
A
medium was optimized for the growth and enzyme production of Saccharomyces
cerevisiae. Varying the components of the standard growth medium it
was found that maximal lipase activity (4.0 units/ml) was expressed
by the organisms when the medium contained 1% oil and 5% yeast extract
as carbon and nitrogen sources, respectively. Optimum temperature
for the production of enzyme was 30°C and the optimum pH was 5.5.
It was observed that aeration and agitation increased both growth
and enzyme production of S. cerevisiae DSM 1848.
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