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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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Bangladesh
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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Bangladesh
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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