Shafkat Shamim Rahman

Isolation of Saccharomyces cerevisiae from pineapple and orange and study of metal’s effectiveness on ethanol production

In view of the anticipated shortage of the traditional supplies of fossil fuels, there is a great deal of interest in the production of ethanol as an alternative biofuel in recent years. The main objective of this research work was to isolate and characterize stress tolerant, high potential ethanol producing yeast strains from various fruit peel. Two yeast isolates from pineapple (Pa) and orange (Or) have been isolated, characterized on the basis of morphological and physic-chemical characters and optimized on ethanol producing capability using sugarcane molasses as substrate. Ethanol production percentage was estimated by Conway method. Isolates were thermotolerant, pH tolerant, ethanol tolerant as well as osmotolerant. They were resistant to Chloramphenicol (30 μg/disc) and Nalidixic acid (30 μg/disc). The isolates showed no killer toxin activity against E. coli. The highest production capacity of the yeasts was found to be 7.39% and 5.02% for Pa and Or, respectively, at pH 5.0, 30 °C temperature in media with an initial reducing sugar concentration of 6.5% for Pa and 5.5% for Or (shaking). Addition of metal ions increased the rate of ethanol production highest to 10.61% by KH2PO4. This study revealed that indigenous yeast isolates could be used to benefit the fuel demand and industrial alcohol industries.

A Study on the Microbiological Status of Mineral Drinking Water

Introduction: Water-borne diseases constitute a major health burden in Bangladesh. The objective of this study was to assess the overall quality of mineral water samples that obtained from different shops of Dhaka city. Material and Methods: To achieve the above-mentioned objective, methods of heterotrophic plate count (HPC) and total coliform count (TCC) were applied. Moreover, isolated colony from mineral water samples were characterized by using biochemical and antimicrobial susceptibility tests. Results: Different water samples showed different HPC ranged from 1.0×10 to 8.00×102. Antimicrobial sensitivity test of some selected bacteria viz S. intermedius, S. aureus, S. felis and S. Saccharolyticus were performed. It was observed that Staphylococcus spp. isolates were susceptible to erythromycin, tetracycline, norfloxacin and ciprofloxacin. Furthermore, a few Staphylococcus spp. isolates were intermediate resistant to penicillin and oxacillin. However, most of the Staphylococcus spp. isolates were resistant to cefixime. Conclusion: The results indicate that mineral water serves as a reservoir of various bacteria and that people in Dhaka city, who are the consumers of these water, might get diseases. This study emphasizes the need for elaborated microbiological examinations of mineral drinking water commonly used in Dhaka city.

Isolation and identification of halotolerant soil bacteria from coastal Patenga area

ObjectiveHalotolerant bacteria have multiple uses viz. fermentation with lesser sterility control and industrial production of bioplastics. Moreover, it may increase the crop productivity of coastal saline lands in Bangladesh by transferring the salt tolerant genes into the plants. The study focused on the isolation and identification of the halotolerant bacteria from three soil samples, collected from coastal Patenga area. The samples were inoculated in nutrient media containing a wide range of salt concentrations.ResultsAll the samples showed 2, 4 and 6% (w/v) salt tolerance. The isolates from Patenga soil (4, 6%) and beach soil (2%) showed catalase activity and all the isolates showed negative results for oxidase activity, indole production, lactose and motility. All the samples provided positive results for dextrose fermentation. Other tests provided mixed results. Based on the morphological characteristics, biochemical tests and ABIS software analysis the isolates fall within the Enterobacteriaceae, Clostridium and Corynebacterium, with a predominance of Vibrios. Overall the isolates can be considered as mild halotolerant, with the best growth observed at lower salinities and no halophilism detected. Among many possibilities, the genes responsible for the salt tolerant trait in these species can be identified, extracted and inserted into the crop plants to form a transgenic plant to result in higher yield for the rest of the year.

Physicochemical and Microbiological Qualities’ Assessment of Popular Bangladeshi Mango Fruit Juice

Introduction: Mango juice has always been considered as a delicious, nutritious popular drink, but processed juice may not always be safe due to chemical and microbial risks. Determination of physicochemical and microbiological qualities of some packed mango juices of Bangladesh will help consumers to know the present scenario. Material and Methods: Six commercially available different juice samples were collected from the market. Carbohydrate profiles were determined using HPLC, crude protein content was calculated using the Kjeldahl method and other parameters were determined by standard AOAC methods. Standard culture techniques were followed to assess the total viable count (TVC), E. coli and other fecal coliforms. Results: The highest quantity of monosaccharide (58.88%) was recorded in the AC1ME5 brand, while the lowest in Homemade (5.648%) and MN1GL2 (9.867%). The maximum content of acidity recorded was 0.24% and minimum 0.21%. The TSS content of all samples varied from 19% to 12%. The highest quantity 6.87% and the lowest 3.62% of reducing sugar were recorded. Most of the mango juices were low in protein and very low/negligible in fat content. Total viable count of different types of fruit juices varied from 1×103 - 3×103 CFU/ml. No significant amount of E. coli and fecal coliform was detected. Conclusion: It can be concluded that the locally available mango juices contain a safe level of nutritional and microbial elements for human consumption, but not highly satisfactory.

A Study Survey on Risk Factors Associated with Breast Cancer in Bangladeshi Population

Background: The occurrence of breast Cancer is a rising concern in Bangladesh. A hospital based case control study was conducted. Methodology: A nationwide representative sample of 100 out of 115 cancer patients aged 20 or older was interviewed at NICRH to provide information on awareness of the risk factors of breast cancer causes in Bangladeshi population. Results and discussion: Highest number of patients was from 40-49 (39%) and 30-39 (27%) year-age group. About 15% patients had direct family history, 21% had early periods. About 14% have got late menopause. If women begin menopause after age 55, the risk increases. 15% women have had not had children, and 10% had their first child after age 30. Study found women using birth control pills (47%), have slightly greater risk. 9% women’s breast feeding lasts below 1 year. And about 7% patient never breast fed their child. About 40% female patients do not walk as exercise. Conclusion: Results suggested a mixture of different factors with Aging and direct family history poses higher risk for breast cancer.