BANGLADESH JOURNAL OF BIOCHEMISTRY

Bangladesh Journal of  Biochemistry
AN INTERNATIONAL JOURNAL IN BIOCHEMICAL SCIENCE

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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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Bangladesh 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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