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Papers by Mozammel Hoq

Bangladesh Journal of Microbiology, Jan 22, 2023

The 'Bacillus cereus group' is one of the largest and most ubiquitous microbes of high economic, ... more The 'Bacillus cereus group' is one of the largest and most ubiquitous microbes of high economic, medical and biodefense importance, comprised of at least eight phylogenetically very closely related Bacillus species. These are B. anthracis, B. cereus, B. thuringiensis, B. mycoides, B. pseudomycoides, B. weihenstephanensis, B. cytotoxicus, and B. toyonensis 1. With the exception of B. cytotoxicus, which is the most divergent of the group with a chromosome of 4.085 Mb, the genomes of member species are highly conserved, with sizes of 5.2 to 5.5 Mb having very similar 16S rRNA gene sequences 2. The most studied members of the group, Bacillus anthracis, B. cereus, and B. thuringiensis are well known and possess substantial pathogenic potential. While B. anthracis is the causative agent of anthrax, few members of B. cereus group are commonly recognized as food poisoning agents, some can also cause localized wound and eye infections as well as systemic diseases 2. Certain B. thuringiensis strains are entomopathogens and are being used commercially as biopesticides, however, some strains have been reported to cause infections in the immunocompromised individuals 2. Despite the presence of high degree phylogenetic relatedness that prompted several researchers to consider the members of the Bacillus cereus group as a unique species, the members demonstrated differences in plasmid content and expression of key regulatory genes. Several approaches were employed to differentiate B. cereus group members including whole-genome DNA hybridization 8 , sequence analysis of the 16S-23S operons, the gyrB-gyrA intergenic spacer region, multilocus enzyme electrophoresis, pulsed-field gel electrophoresis analysis 4 , amplified fragment length polymorphism 6 , virulence factors, arbitrary PCR, multiplex PCR and PCR-restriction fragment length polymorphism 6. However, the need to adopt a rapid and simpler method remained an issue to ponder.. HiCrome TM Bacillus Agar is a selective and differential media which is recommended for the isolation and differentiation amongst various species of Bacillus. This medium is based on the formulation of MYP (Mannitol, egg yolk, polymyxin) agar where different Bacillus sp. show different colored colonies 9. However, culture-based method of identification does not always

Biology and medicine, Nov 9, 2016

Genome sequence study of an industrially-important strain, Bacillus subtilis M9, a mutant version... more Genome sequence study of an industrially-important strain, Bacillus subtilis M9, a mutant version of wild strain Bacillus subtilis MZK05 was conducted to uncover genetic factors responsible for enhanced serine proteases expression in addition to its other industrial enzymes, metabolites and bacteriocins producing efficacy. The wild type and the mutant genome contained a size of 4,145,727 and 4,045,950 bp, with 4,352 and 4,383 genes; and 477 and 478 subsystems respectively. Genomic comparison with 31 B. subtilis sourced from different countries showed both wild and mutant shared same type of genome structure with 20 others. Moreover, 6,000 kb pangenome showed that they share 3082, 1449, and 25757 core, unique and accessory genes respectively. A sum of 32,559 mutations were found with three major genomic structural changes in the upstream and downstream of an extracellular alkaline serine protease, AprX and a periplasmic serine protease, HtrC in M9 genome when compared to the wild typ...

Chemical pesticides were introduced in Bangladesh with a great hope to protect the crops from pes... more Chemical pesticides were introduced in Bangladesh with a great hope to protect the crops from pests. But their random and indiscriminate use has created a very serious health and environmental problems. It was therefore very necessary to find a better alternative. This book gives invaluable information on the current trends in the usage of pesticide and various research projects on biopesticides in Bangladesh. Hazardous impacts of chemical pesticides, global overview of biopesticides, importance of Bacillus thuringiensis as a biopesticide have been discussed in the book. Moreover, it has published the updated information on some research works on biopesticides in Bangladesh. A detail information on the impact of Integrated Pest Management (IPM) implementation in Bangladesh has been included in the book. Finally it has described about the new agricultural extension policy in Bangladesh. The book will be especially useful to the researchers, programme and project implementers, policy ...

Microbial Bioactives, 2018

Cancer treatment remains as an expensive process due to the cost of sophisticated infrastructure ... more Cancer treatment remains as an expensive process due to the cost of sophisticated infrastructure development as well as its maintenance with skilled personnel. At the same time, the success rate is not very inspiring since non-specific target oriented medication could cause other health complexities leading to death. Research for alternative therapies aimed at minimizing the side effects of treatments and increasing the survival rates of patients includes routine explorations for anticancer agents from numerous sources (e.g. microbes, plants and nanoparticles). Anticancer activities of several bacterial components especially from Bacillus spp. were reported in many scientific reports. For economic production of these agents, potential strains from this genus could be feasible and sustainable for their long and successful utilization in industries. The review is therefore, focused on describing the available anticancer and anti-proliferative agents reported worldwide from Bacillus spp.

Microbial Bioactives, 2018

Background. Due to certain limitations, the bioprocess development for protease production needs ... more Background. Due to certain limitations, the bioprocess development for protease production needs more convenient and realistic statistical approach instead of conventional optimization technique. For an economic bioprocess with enhanced protease yield, Response Surface Methodology (RSM) based on Central Composite Design (CCD) was employed and evaluated in this study. Materials and methods. The fermentation was performed with a mutant strain, Bacillus licheniformis MZK05M9 (BlM9) using molasses, urea and CaCl 2 .2H 2 O as carbon, nitrogen and trace element sources respectively in shake flask. The conditions for fermentation were maintained with temperature, pH and agitation at 37°C, 7.5 and 150 rpm respectively. The required number of trials were determined by investigating each variable (Molasses, Urea and CaCl 2) at five levels:-α,-1, 0, +1 and +α through CCD with protease yield as the response function and the interaction effects as well as optimal parameters were obtained by using Minitab software. The significance of the independent variables and their interactions were tested by means of analysis of variance (ANOVA) with a 95% confidence level and 3-D surface plots were developed through RSM. Results. Upon 20 trials, the optimum values of the tested variables for maximum alkaline protease production as predicted through CCD and RSM were as 0.63%, 0.16%, and 0.11% (w/v) for Molasses, Urea and CaCl 2 .2H 2 O, respectively. The protease activity in Conventionally Optimized (CO) medium was 410 U/ ml and it was predicted as 463.1 U/ ml for statistically optimized medium. Upon experiments with the optimized medium, the protease activity was estimated as 560 U/ ml which was 36.6% (i.e. 1.36 fold) higher than that of CO medium. Conclusion. The efficiency of the enzyme in solubilizing the whole feathers was also assessed which indicated that the enzyme produced with cheap substrates could be utilized as a cost effective and eco-friendly agent in poultry feed formulation, leather processing etc.

Bangladesh Pharmaceutical Journal, 2018

Investigations were performed to find out new microbial enzymes as thrombolytics having better ef... more Investigations were performed to find out new microbial enzymes as thrombolytics having better efficacy and specificity. Mutant strain of Bacillus species, B. licheniformis MZK05M9 was cultured in modified urea-glucose media followed by purification using ammonium sulphate precipitation and ultrafiltration through centricon tube of specific MWCO value. The production method yielded 823.42 units/mg of the crude enzyme from mutant strain MZK05M9 and after purification 37695.64 units/mg. The molecular weight of the purified enzyme was estimated as 27.2 kDa and purification increased its specific activity to 16.5 fold with a recovery of 10%. The purified proteases were identified as serine proteases by irreversible inhibition of activity with phenylmethylsulfonyl fluoride (PMSF) and it exhibited 32.84% thrombolytic activity, by in vitro clot lysis assay. Stability studies showed that crude enzyme from mutant strain MZK05M9 remained stable up to a temperature of 45˚C and showed maximum stability at pH range 7.5 to 8.5. Our observation indicates that proteases produced by Bacillus licheniformis mutant have the potential to be developed as a viable thrombolytic agent.

Malaysian Journal of Microbiology, 2016

Aims: Bacillus licheniformis MZK-05 is a keratinolytic bacterium having potential in dehairing of... more Aims: Bacillus licheniformis MZK-05 is a keratinolytic bacterium having potential in dehairing of leather and feather hydrolysis. The present study aimed at to improving the production level of keratinase through gene cloning and expression of recombinant keratinase. Methodology and results: Bacillus licheniformis MZK-05 produced an amplicon of 1,156 bp in a polymerase chain reaction while targeting the gene, kerA, responsible for the enzyme keratinase. The amplicon was subsequently cloned into the plasmid vector pGEX-6p-2 for expression in Escherichia coli BL21. A 58 kD GST-KerA fusion protein was expressed upon IPTG induction which was eventually cleaved by PreScission protease that produced a 39 kD protein. A corresponding increase in proteolytic (312 U/mL) and keratinolytic (196 U/mL) activity were observed with the expressed keratinase. Specific enzyme activities for protease and keratinase, an indication of efficiency of the enzyme, were 2621.84 U/mg and 1647 U/mg, respectively and the specific keratinase activity was the highest activity ever reported by any recombinant bacterial strain. Conclusion, significance and impact study: Since the production of keratinase by wild type strain is limited to a certain level, the industrial need could be met by improving the production level through gene cloning and expression of recombinant keratinase. In this connection, the cloning of kerA gene from B. licheniformis MZK-05 into pGEX-6p-2 vector, its expression in Escherichia coli BL21 host and prediction of 3-D model of the expressed protein were performed which will be the basis for industrial production of keratinase in Bangladesh.

Bt Research, 2015

Genetic diversity is highly relevant and significant in discovering novel insecticidal genes in B... more Genetic diversity is highly relevant and significant in discovering novel insecticidal genes in Bacillus thuringiensis ( Bt ) strains and to deal with the problems of emerging insect resistance towards Bt biopesticides. In view of this, Random Amplified Polymorphic DNA (RAPD)-PCR analysis was performed with a decamer AGCTCAGCCA for molecular typing of 177 Bt strains of Bangladesh to determine their genetic diversity. These Bt strains were allocated into 15 genomic types with their binary matrices as determined from the dendrogram based on a standardized distance in scale bar. Genotype 9 and 11 were the largest among others, each containing more than 25% of the Bt strains. The average diversity index, as deduced for each group by cluster: isolate ratio at a specific distance, was higher for locations (0.27 ± 0.098) than that for biotypes (0.23 ± 0.046) which indicates an unmingled and vertical transfer of biochemical properties among the strains. Prevalence of agriculturally important subgroups of cry1 gene in indigenous Bt strains was also determined where cry1Aa and cry1Ca gene were found to be the most prevalent (21.74%). While analyzing the distribution pattern of cry genes, they were observed to be present in all RAPD- genotypes but genotype 10 and were most prevalent in genotypes 1, 6 and 9. The phylogeny reconstruction among the strains was performed by neighbor-joining method with the 16S rRNA gene sequences and the correlation among the phylogeny, RAPD genotypes, Biotypes and presence of cry genes were analyzed.

Journal of Fermentation Technology

Bangladesh Journal of Scientific and Industrial Research, 1970

Feeds and fertilizer production from tanned skin-cut wastes is the most direct phenomenon of chro... more Feeds and fertilizer production from tanned skin-cut wastes is the most direct phenomenon of chromium eco-toxicity leading to food chain contamination in Bangladesh. Tanning industries of Hazaribagh at Dhaka process some 220 t of hide per day with release of 600-1000 Kg tanned skin-cut waste (SCW) per ton processed hide. The SCW is protein-rich and unscientifically used to produce poultry and fish feeds, and organic fertilizer. A huge migration of chromium can happen into poultry products, fish and vegetables, and further bio-magnify into food chain. The target population is also huge. It is reported that feed ingredients produced from SCW contained chromium at levels as high as 2.49%. As Cr(VI) is the most toxic species of chromium, reduction of Cr(VI) to Cr(III) prior to be used as feed ingredients and fertilizers can ensure safer input of chromium in toxicological point of view. Samples have been collected to isolate microorganisms from effluent sites of Hazaribagh tanning area u...

Bangladesh Journal of Microbiology, 2008

A culture medium was optimized for the production of keratinolytic protease by a newly isolated s... more A culture medium was optimized for the production of keratinolytic protease by a newly isolated strain of Bacillus licheniformis MZK-03 in shake-flask culture. Based on the results of preliminary experiments, feather mill, molasses and trace elements were found to be major variables in keratinolytic protease production. The concentrations of these ingredients were optimized by using two statistical approaches, namely Box-Wilson method and central composite design. The optimized culture medium, finally determined by using the statistical approaches, composed of 0.95% feather mill, 0.12% molasses and 1.44% trace elements. The keratinolytic protease production was increased by approximately 2-fold when the strain was grown in the optimized medium (95.2 U/ml) compared to the un-optimized medium (56.05 U/ml). Keywords: Keratinolytic protease, Optimization, Bacillus licheniformis MZK-03, Statistical designsDOI: http://dx.doi.org/10.3329/bjm.v24i1.1238 Bangladesh J Microbiol, Volume 24, Nu...

Bangladesh Journal of Medical Microbiology, 2012

Nosocomial infection is an endemic problem encountered in hospitalized patients all over the worl... more Nosocomial infection is an endemic problem encountered in hospitalized patients all over the world including Bangladesh. The present prospective study was carried out on 152 patients who were admitted in Dhaka Medical College Hospital and BIRDEM Hospital over a two years period to determine the organisms responsible for nosocomial infection, their antibiotic susceptibility pattern, sources and the impact of hospital infection on patient management. Samples were collected from postoperative wounds, post catheterized urinary tract infection (UTI) and diabetic wounds. The patients without postoperative wound infection were taken as control group. To trace the sources of infection the samples from the different objects of the hospital environment were studied. The collected samples were cultured and isolated organisms were identified by colony morphology, gram staining and necessary biochemical tests. The identified organisms were tested for antibiogram pattern and plasmid profile. The ...

Bangladesh Journal of Microbiology, 1970

Fossil fuel depletion and limitations turn scientists to develop alternative fuels as well as bio... more Fossil fuel depletion and limitations turn scientists to develop alternative fuels as well as biofuels. Cheap cellulosic biomass could be used as raw materials for production of ethanol. Water hyacinth (Eichhornia crassipes) and Azolla (Azolla pinnata) are the two biomass resources considered in this study. The purpose of this study was to produce ethanol using water hyacinth and Azolla as substrates used to produce ethanol by using two yeasts presumptively identified as Sachharomyces cerevisiae (Sc-SR4, Sc-MR8) and Kluyveromyces marxianus (Km-SR3). For saccharification, water hyacinth and Azolla were pretreated with different concentrations (0.25 to 1.0%) of sulphuric acid. D-glucose and reducing sugar yield was found higher for Azolla (40% of dry weight) than water hyacinth (25.2% of dry weight). The ethanol yield was higher with water hyacinth, (0.32g/g ethanol), than that of Azolla, (0.20g/g ethanol). Acid and heat treatment both affected saccharification. The water hyacinth hyd...

World Journal of Microbiology & Biotechnology - WORLD J MICROBIOL BIOTECHNOL, 1998

Cellulase-free xylanase production by T. lanuginosus MH4 was investigated in a 3-litre stirred ta... more Cellulase-free xylanase production by T. lanuginosus MH4 was investigated in a 3-litre stirred tank bioreactor under different agitation rates and an aeration rate of 1v/v/m. The cultivation time in the bioreactor was reduced significantly over that in shake culture conditions. A xylanase productivity of 0.1 mkat1-1h-1 was achieved on xylan in the bioreactor. This was nearly double to that obtained in shake culture. The agitation rates influenced both growth and enzyme secretion in the bioreactor. The highest level of biomass concentration and activities of both xylanase and ß-xylosidase were obtained at 150 revmin-1

World Journal of Microbiology & Biotechnology, 1992

Fourteen strains ofVibrio furnissii, isolated from different ulcerated areas of eel, were tested ... more Fourteen strains ofVibrio furnissii, isolated from different ulcerated areas of eel, were tested to check their enterotoxicity in an animal model. Most strains caused fluid accumulation in ileal loop tests after serial passages and culture filtrates of most of the strains caused induration and increase in vascular permeability in rabbit skin. Production of extracellular haemolysin was also detected in all the culture filtrates. All of these observations clearly establish the enterotoxicity of these organisms.

Bangladesh Journal of Microbiology, Jan 22, 2023

The 'Bacillus cereus group' is one of the largest and most ubiquitous microbes of high economic, ... more The 'Bacillus cereus group' is one of the largest and most ubiquitous microbes of high economic, medical and biodefense importance, comprised of at least eight phylogenetically very closely related Bacillus species. These are B. anthracis, B. cereus, B. thuringiensis, B. mycoides, B. pseudomycoides, B. weihenstephanensis, B. cytotoxicus, and B. toyonensis 1. With the exception of B. cytotoxicus, which is the most divergent of the group with a chromosome of 4.085 Mb, the genomes of member species are highly conserved, with sizes of 5.2 to 5.5 Mb having very similar 16S rRNA gene sequences 2. The most studied members of the group, Bacillus anthracis, B. cereus, and B. thuringiensis are well known and possess substantial pathogenic potential. While B. anthracis is the causative agent of anthrax, few members of B. cereus group are commonly recognized as food poisoning agents, some can also cause localized wound and eye infections as well as systemic diseases 2. Certain B. thuringiensis strains are entomopathogens and are being used commercially as biopesticides, however, some strains have been reported to cause infections in the immunocompromised individuals 2. Despite the presence of high degree phylogenetic relatedness that prompted several researchers to consider the members of the Bacillus cereus group as a unique species, the members demonstrated differences in plasmid content and expression of key regulatory genes. Several approaches were employed to differentiate B. cereus group members including whole-genome DNA hybridization 8 , sequence analysis of the 16S-23S operons, the gyrB-gyrA intergenic spacer region, multilocus enzyme electrophoresis, pulsed-field gel electrophoresis analysis 4 , amplified fragment length polymorphism 6 , virulence factors, arbitrary PCR, multiplex PCR and PCR-restriction fragment length polymorphism 6. However, the need to adopt a rapid and simpler method remained an issue to ponder.. HiCrome TM Bacillus Agar is a selective and differential media which is recommended for the isolation and differentiation amongst various species of Bacillus. This medium is based on the formulation of MYP (Mannitol, egg yolk, polymyxin) agar where different Bacillus sp. show different colored colonies 9. However, culture-based method of identification does not always

Biology and medicine, Nov 9, 2016

Genome sequence study of an industrially-important strain, Bacillus subtilis M9, a mutant version... more Genome sequence study of an industrially-important strain, Bacillus subtilis M9, a mutant version of wild strain Bacillus subtilis MZK05 was conducted to uncover genetic factors responsible for enhanced serine proteases expression in addition to its other industrial enzymes, metabolites and bacteriocins producing efficacy. The wild type and the mutant genome contained a size of 4,145,727 and 4,045,950 bp, with 4,352 and 4,383 genes; and 477 and 478 subsystems respectively. Genomic comparison with 31 B. subtilis sourced from different countries showed both wild and mutant shared same type of genome structure with 20 others. Moreover, 6,000 kb pangenome showed that they share 3082, 1449, and 25757 core, unique and accessory genes respectively. A sum of 32,559 mutations were found with three major genomic structural changes in the upstream and downstream of an extracellular alkaline serine protease, AprX and a periplasmic serine protease, HtrC in M9 genome when compared to the wild typ...

Chemical pesticides were introduced in Bangladesh with a great hope to protect the crops from pes... more Chemical pesticides were introduced in Bangladesh with a great hope to protect the crops from pests. But their random and indiscriminate use has created a very serious health and environmental problems. It was therefore very necessary to find a better alternative. This book gives invaluable information on the current trends in the usage of pesticide and various research projects on biopesticides in Bangladesh. Hazardous impacts of chemical pesticides, global overview of biopesticides, importance of Bacillus thuringiensis as a biopesticide have been discussed in the book. Moreover, it has published the updated information on some research works on biopesticides in Bangladesh. A detail information on the impact of Integrated Pest Management (IPM) implementation in Bangladesh has been included in the book. Finally it has described about the new agricultural extension policy in Bangladesh. The book will be especially useful to the researchers, programme and project implementers, policy ...

Microbial Bioactives, 2018

Cancer treatment remains as an expensive process due to the cost of sophisticated infrastructure ... more Cancer treatment remains as an expensive process due to the cost of sophisticated infrastructure development as well as its maintenance with skilled personnel. At the same time, the success rate is not very inspiring since non-specific target oriented medication could cause other health complexities leading to death. Research for alternative therapies aimed at minimizing the side effects of treatments and increasing the survival rates of patients includes routine explorations for anticancer agents from numerous sources (e.g. microbes, plants and nanoparticles). Anticancer activities of several bacterial components especially from Bacillus spp. were reported in many scientific reports. For economic production of these agents, potential strains from this genus could be feasible and sustainable for their long and successful utilization in industries. The review is therefore, focused on describing the available anticancer and anti-proliferative agents reported worldwide from Bacillus spp.

Microbial Bioactives, 2018

Background. Due to certain limitations, the bioprocess development for protease production needs ... more Background. Due to certain limitations, the bioprocess development for protease production needs more convenient and realistic statistical approach instead of conventional optimization technique. For an economic bioprocess with enhanced protease yield, Response Surface Methodology (RSM) based on Central Composite Design (CCD) was employed and evaluated in this study. Materials and methods. The fermentation was performed with a mutant strain, Bacillus licheniformis MZK05M9 (BlM9) using molasses, urea and CaCl 2 .2H 2 O as carbon, nitrogen and trace element sources respectively in shake flask. The conditions for fermentation were maintained with temperature, pH and agitation at 37°C, 7.5 and 150 rpm respectively. The required number of trials were determined by investigating each variable (Molasses, Urea and CaCl 2) at five levels:-α,-1, 0, +1 and +α through CCD with protease yield as the response function and the interaction effects as well as optimal parameters were obtained by using Minitab software. The significance of the independent variables and their interactions were tested by means of analysis of variance (ANOVA) with a 95% confidence level and 3-D surface plots were developed through RSM. Results. Upon 20 trials, the optimum values of the tested variables for maximum alkaline protease production as predicted through CCD and RSM were as 0.63%, 0.16%, and 0.11% (w/v) for Molasses, Urea and CaCl 2 .2H 2 O, respectively. The protease activity in Conventionally Optimized (CO) medium was 410 U/ ml and it was predicted as 463.1 U/ ml for statistically optimized medium. Upon experiments with the optimized medium, the protease activity was estimated as 560 U/ ml which was 36.6% (i.e. 1.36 fold) higher than that of CO medium. Conclusion. The efficiency of the enzyme in solubilizing the whole feathers was also assessed which indicated that the enzyme produced with cheap substrates could be utilized as a cost effective and eco-friendly agent in poultry feed formulation, leather processing etc.

Bangladesh Pharmaceutical Journal, 2018

Investigations were performed to find out new microbial enzymes as thrombolytics having better ef... more Investigations were performed to find out new microbial enzymes as thrombolytics having better efficacy and specificity. Mutant strain of Bacillus species, B. licheniformis MZK05M9 was cultured in modified urea-glucose media followed by purification using ammonium sulphate precipitation and ultrafiltration through centricon tube of specific MWCO value. The production method yielded 823.42 units/mg of the crude enzyme from mutant strain MZK05M9 and after purification 37695.64 units/mg. The molecular weight of the purified enzyme was estimated as 27.2 kDa and purification increased its specific activity to 16.5 fold with a recovery of 10%. The purified proteases were identified as serine proteases by irreversible inhibition of activity with phenylmethylsulfonyl fluoride (PMSF) and it exhibited 32.84% thrombolytic activity, by in vitro clot lysis assay. Stability studies showed that crude enzyme from mutant strain MZK05M9 remained stable up to a temperature of 45˚C and showed maximum stability at pH range 7.5 to 8.5. Our observation indicates that proteases produced by Bacillus licheniformis mutant have the potential to be developed as a viable thrombolytic agent.

Malaysian Journal of Microbiology, 2016

Aims: Bacillus licheniformis MZK-05 is a keratinolytic bacterium having potential in dehairing of... more Aims: Bacillus licheniformis MZK-05 is a keratinolytic bacterium having potential in dehairing of leather and feather hydrolysis. The present study aimed at to improving the production level of keratinase through gene cloning and expression of recombinant keratinase. Methodology and results: Bacillus licheniformis MZK-05 produced an amplicon of 1,156 bp in a polymerase chain reaction while targeting the gene, kerA, responsible for the enzyme keratinase. The amplicon was subsequently cloned into the plasmid vector pGEX-6p-2 for expression in Escherichia coli BL21. A 58 kD GST-KerA fusion protein was expressed upon IPTG induction which was eventually cleaved by PreScission protease that produced a 39 kD protein. A corresponding increase in proteolytic (312 U/mL) and keratinolytic (196 U/mL) activity were observed with the expressed keratinase. Specific enzyme activities for protease and keratinase, an indication of efficiency of the enzyme, were 2621.84 U/mg and 1647 U/mg, respectively and the specific keratinase activity was the highest activity ever reported by any recombinant bacterial strain. Conclusion, significance and impact study: Since the production of keratinase by wild type strain is limited to a certain level, the industrial need could be met by improving the production level through gene cloning and expression of recombinant keratinase. In this connection, the cloning of kerA gene from B. licheniformis MZK-05 into pGEX-6p-2 vector, its expression in Escherichia coli BL21 host and prediction of 3-D model of the expressed protein were performed which will be the basis for industrial production of keratinase in Bangladesh.

Bt Research, 2015

Genetic diversity is highly relevant and significant in discovering novel insecticidal genes in B... more Genetic diversity is highly relevant and significant in discovering novel insecticidal genes in Bacillus thuringiensis ( Bt ) strains and to deal with the problems of emerging insect resistance towards Bt biopesticides. In view of this, Random Amplified Polymorphic DNA (RAPD)-PCR analysis was performed with a decamer AGCTCAGCCA for molecular typing of 177 Bt strains of Bangladesh to determine their genetic diversity. These Bt strains were allocated into 15 genomic types with their binary matrices as determined from the dendrogram based on a standardized distance in scale bar. Genotype 9 and 11 were the largest among others, each containing more than 25% of the Bt strains. The average diversity index, as deduced for each group by cluster: isolate ratio at a specific distance, was higher for locations (0.27 ± 0.098) than that for biotypes (0.23 ± 0.046) which indicates an unmingled and vertical transfer of biochemical properties among the strains. Prevalence of agriculturally important subgroups of cry1 gene in indigenous Bt strains was also determined where cry1Aa and cry1Ca gene were found to be the most prevalent (21.74%). While analyzing the distribution pattern of cry genes, they were observed to be present in all RAPD- genotypes but genotype 10 and were most prevalent in genotypes 1, 6 and 9. The phylogeny reconstruction among the strains was performed by neighbor-joining method with the 16S rRNA gene sequences and the correlation among the phylogeny, RAPD genotypes, Biotypes and presence of cry genes were analyzed.

Journal of Fermentation Technology

Bangladesh Journal of Scientific and Industrial Research, 1970

Feeds and fertilizer production from tanned skin-cut wastes is the most direct phenomenon of chro... more Feeds and fertilizer production from tanned skin-cut wastes is the most direct phenomenon of chromium eco-toxicity leading to food chain contamination in Bangladesh. Tanning industries of Hazaribagh at Dhaka process some 220 t of hide per day with release of 600-1000 Kg tanned skin-cut waste (SCW) per ton processed hide. The SCW is protein-rich and unscientifically used to produce poultry and fish feeds, and organic fertilizer. A huge migration of chromium can happen into poultry products, fish and vegetables, and further bio-magnify into food chain. The target population is also huge. It is reported that feed ingredients produced from SCW contained chromium at levels as high as 2.49%. As Cr(VI) is the most toxic species of chromium, reduction of Cr(VI) to Cr(III) prior to be used as feed ingredients and fertilizers can ensure safer input of chromium in toxicological point of view. Samples have been collected to isolate microorganisms from effluent sites of Hazaribagh tanning area u...

Bangladesh Journal of Microbiology, 2008

A culture medium was optimized for the production of keratinolytic protease by a newly isolated s... more A culture medium was optimized for the production of keratinolytic protease by a newly isolated strain of Bacillus licheniformis MZK-03 in shake-flask culture. Based on the results of preliminary experiments, feather mill, molasses and trace elements were found to be major variables in keratinolytic protease production. The concentrations of these ingredients were optimized by using two statistical approaches, namely Box-Wilson method and central composite design. The optimized culture medium, finally determined by using the statistical approaches, composed of 0.95% feather mill, 0.12% molasses and 1.44% trace elements. The keratinolytic protease production was increased by approximately 2-fold when the strain was grown in the optimized medium (95.2 U/ml) compared to the un-optimized medium (56.05 U/ml). Keywords: Keratinolytic protease, Optimization, Bacillus licheniformis MZK-03, Statistical designsDOI: http://dx.doi.org/10.3329/bjm.v24i1.1238 Bangladesh J Microbiol, Volume 24, Nu...

Bangladesh Journal of Medical Microbiology, 2012

Nosocomial infection is an endemic problem encountered in hospitalized patients all over the worl... more Nosocomial infection is an endemic problem encountered in hospitalized patients all over the world including Bangladesh. The present prospective study was carried out on 152 patients who were admitted in Dhaka Medical College Hospital and BIRDEM Hospital over a two years period to determine the organisms responsible for nosocomial infection, their antibiotic susceptibility pattern, sources and the impact of hospital infection on patient management. Samples were collected from postoperative wounds, post catheterized urinary tract infection (UTI) and diabetic wounds. The patients without postoperative wound infection were taken as control group. To trace the sources of infection the samples from the different objects of the hospital environment were studied. The collected samples were cultured and isolated organisms were identified by colony morphology, gram staining and necessary biochemical tests. The identified organisms were tested for antibiogram pattern and plasmid profile. The ...

Bangladesh Journal of Microbiology, 1970

Fossil fuel depletion and limitations turn scientists to develop alternative fuels as well as bio... more Fossil fuel depletion and limitations turn scientists to develop alternative fuels as well as biofuels. Cheap cellulosic biomass could be used as raw materials for production of ethanol. Water hyacinth (Eichhornia crassipes) and Azolla (Azolla pinnata) are the two biomass resources considered in this study. The purpose of this study was to produce ethanol using water hyacinth and Azolla as substrates used to produce ethanol by using two yeasts presumptively identified as Sachharomyces cerevisiae (Sc-SR4, Sc-MR8) and Kluyveromyces marxianus (Km-SR3). For saccharification, water hyacinth and Azolla were pretreated with different concentrations (0.25 to 1.0%) of sulphuric acid. D-glucose and reducing sugar yield was found higher for Azolla (40% of dry weight) than water hyacinth (25.2% of dry weight). The ethanol yield was higher with water hyacinth, (0.32g/g ethanol), than that of Azolla, (0.20g/g ethanol). Acid and heat treatment both affected saccharification. The water hyacinth hyd...

World Journal of Microbiology & Biotechnology - WORLD J MICROBIOL BIOTECHNOL, 1998

Cellulase-free xylanase production by T. lanuginosus MH4 was investigated in a 3-litre stirred ta... more Cellulase-free xylanase production by T. lanuginosus MH4 was investigated in a 3-litre stirred tank bioreactor under different agitation rates and an aeration rate of 1v/v/m. The cultivation time in the bioreactor was reduced significantly over that in shake culture conditions. A xylanase productivity of 0.1 mkat1-1h-1 was achieved on xylan in the bioreactor. This was nearly double to that obtained in shake culture. The agitation rates influenced both growth and enzyme secretion in the bioreactor. The highest level of biomass concentration and activities of both xylanase and ß-xylosidase were obtained at 150 revmin-1

World Journal of Microbiology & Biotechnology, 1992

Fourteen strains ofVibrio furnissii, isolated from different ulcerated areas of eel, were tested ... more Fourteen strains ofVibrio furnissii, isolated from different ulcerated areas of eel, were tested to check their enterotoxicity in an animal model. Most strains caused fluid accumulation in ileal loop tests after serial passages and culture filtrates of most of the strains caused induration and increase in vascular permeability in rabbit skin. Production of extracellular haemolysin was also detected in all the culture filtrates. All of these observations clearly establish the enterotoxicity of these organisms.