Pasteurization remains as an important process that makes milk safe from pathogens and increases milk’s shelf life without altering the taste and the nutritional value. But, still many people drink unpasteurized milk either because people do not know how to pasteurize the raw milk at home, or because they prefer minimally processed food. Herein, we demonstrated that simply heating milk over a kitchen stove up to 65° C can produce pasteurized quality of milk by reducing the total number of bacteria within the limit (<20,000 CFU.mL-1) of U.S. Grade “A” Pasteurized Milk Ordinance, killing pathogens like coliforms, E. coli, Vibrio, Salmonella, Lactobacillus spp., Pseudomonas and Staphylococcus aureus etc., inactivating milk’s endogenous heat-resistant alkaline phosphatase (ALP), and extending milk’s shelf life similar to pasteurized milk. However, heating milk to 75°C showed greater effectiveness in killing pathogens than that of standard pasteurization (62.5°C for 30 min). Importantly, the key nutritional elements of milk including total protein, lipid, lactose, vitamin B2 and calcium remained protected even at 75°C. Thus, simply heating milk on a kitchen stove up to 65°C-75°C has been shown quick, cost-effective, an energy-saving in-home pasteurization technique to produce safe and nourishing milk with increased shelf life.

The exploration for marine sponge associated novel microbes, producing rich and highly potential therapeutic metabolites, could diversify the scopes in life sciences. Since this has remained mostly untouched, the research was carried out to explore the bioactive potential of a marine sponge, Callyspongia diffusa associated microbes. The strains selected from the C. diffusa were Pseudomonas fluorescens and Penicillum citrinum and their cell free extracts were tested for hemolytic activity on sheep blood agar media and antioxidant activity was assessed with lyophilized cell free extracts. Anticancer activity was performed by cytotoxicity assay against HEP-2 cell lines. Cell free extracts of both P. fluorescens and P. citrinum demonstrated a-hemolysis on sheep blood agar. The lyophilized culture filtrate of P. fluorescens BCPBMS-1 and P. citrinum exhibited concentration dependent antioxidant activity revealing a positive linear relationship and ca. 85% and 74% antioxidant activities were obtained respectively with 1.0 mg/ ml of each of the sample. In case of cytotoxicity assay, P. citrinum demonstrated maximum viability of 96.61% at 1.95 µg/ ml of lyophilized culture filtrate and minimum viability of 20.33% at 1000 µg/ ml. The study proved that both P. fluorescens BCPBMS-1 and P. citrinum strains produce bioactive metabolites with hemolytic activity and antioxidant activity whereas P. citrinum could be a valuable resource for anticancer metabolites.

Background: The present study was aimed to isolate phytase producing bacteria and optimize the physicochemical parameters of their phytase production. Materials and methods: Four bacterial isolates (Phs4, Phs5, Phs6, and Phs8), based on clear zone formation on phytase screening medium, were selected and tested for finding out the highest phytase producing strain. The production of phytase was then optimized and its biochemical properties were determined to judge the applicability of phytase as a digestive aid in animal feed. Results: The 4 bacterial isolates (Phs4, Phs5, Phs6 and Phs8) were identified by morphological, cultural, biochemical and molecular characterization as Burkholderia cepacia, Escherichia coli, Klebsiella pneumoniae and Klebsiella sp. respectively. Of these isolates, Phs8 (Klebsiella sp.) was found to produce maximum phytase in shake culture in a basal medium containing Na-phytate at 37oC and pH 5.5 after 72 hours of incubation. The omission of Na-phytate from the medium almost completely abolished the phytase production capacity of the isolate and thus signified its important role as an inducer. Among the different complex carbon sources, viz., glucose, wheat bran, rice bran and chickpea, maximum phytase production (94 unit/ ml) was obtained with wheat bran under comparable cultivation conditions. The phytase works best at a temperature of 37oC and pH of 4.0 with a wide temperature stability (more than 80% activity up to 80oC) and wide pH stability (more than 80% activity within a range of 3-8). Although Zn2+, Co2+, and Fe2+ slightly increased the phytase activity Cu2+ and Mg2+ strongly inhibited the enzyme. Conclusion: The present findings will be very useful for the development of a bioprocess of the enzyme for its large-scale production at the pilot and finally at the commercial level.

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 CaCl2.2H2O 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 CaCl2) at five levels: -a, -1, 0, +1 and +a 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 CaCl2.2H2O 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.

Background: The aim of the present study was to evaluate the anticariogenic activities of commercially available dentifrices such as, toothpastes and mouthwashes against the most prominent cariogenic bacteria S. mutans. Methods: Agar well diffusion method was employed to investigate the antibacterial activity against newly isolated clinical strains. Statistical analysis was performed using SPSS version 20 and one-way ANOVA and student t-test were used to compare the zone of inhibition. Results: We found that most of the commercially available dentifrices have antibacterial activity against S. mutans clinical isolates. We also found that fluoride and triclosan containing toothpaste has comparatively higher antibacterial effect than others. In addition, we observed that mouthwashes have relatively lower antibacterial activity than the toothpastes. Conclusions: In sum, our study indicated that sodium fluoride and triclosan containing toothpastes can be effectively used to maintain a good oral hygiene to prevent dental caries and other related diseases.

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.

Background: Many biotic and abiotic soil components affect entomopathogenic nematode (EPN’s) activity, infectivity, host finding ability and the rate of reproduction. Since, copper being an essential element, could be toxic at its elevated concentrations in soils, the study was aimed therefore to evaluate the biological effect of Cu ion and safer alternatives, i.e. Schiff base ligands and their copper complexes on EPN’s juveniles. Methods: Two novel Schiff base ligands of 2-amino 3- cyano 1, 5 diphenylpyrrole and salicylaldehyde (HL1) or 2- hydroxy11-naphthylaldehyde (HL2) and their copper (II) complexes were synthesized and characterized. Their effect on the infectivity and reproduction potential of the Egyptian entomopathogenic nematodes (EPN’s) Heterorhabditis bacteriophora and the imported Steinernema carpocapsae were tested at 1.5 mg/l and 11.0 mg/l. Results: The infectivity of Cu (II) ion treated H. bacteriophora and S. carpocapsae juveniles (at low and high concentrations) generally reduced, (33.30 % and 11.50%) and (88% and 75%) respectively, as compared with that of control. The infectivity of the ligands and complexes treated H. bacteriophora and S. carpocapsae juveniles at both concentrations matches that of the non-treated nematodes (100%). The reproduction of H. bacteriophora and S. carpocapsae decreased with increasing concentrations of copper (II), the ligands (HL1, HL2) and complexes (C1, C2) except in HL1 for H. bacteriophora and C2 for S. carpocapsae. The difference in reproduction potentials of the tested EPN’s due to the dose variations of the agents was observed to be insignificant. Conclusions: Although the pollution of soil with copper (II) ions affects nematode infectivity and reproduction potential, Schiff base ligands and their copper complexes were found to be less harmful and hence the latter could be used in combination with fertilizers to overcome one of the abiotic factors enhancing the field efficacy of EPN.

Background: The determinative bacteriology currently available in the suburbs of Dhaka city mainly involves culture-based identification techniques. Incorporation of extensive biochemical characterization could enhance the efficiency of the existing methods and reduce the risk of wrong medication. The study was aimed, in this connection, at reassessment of clinical pathogens in the suburbs of Dhaka city through biochemical and molecular analysis. Methods: To assess the accuracy of identification of clinical pathogens by the diagnostic facilities of suburbs of Dhaka city, we were provided with previously identified clinical strains from different diagnostic facilities along with their clinical data. The etiological agents, were analyzed based on the cultural characteristics on different selective agar media and biochemical properties. The API20E profiles of the pathogens were analyzed to identify the organisms. Furthermore, to verify the results of API20E, 16s rRNA genes were sequenced and their phylogenetic relationship was checked in NCBI database. Result: The gram-negative clinical strains that the diagnostic facilities (DFI) provided were Escherichia coli, Klebsiella, and Pseudomonas. We further reassessed their identities among which two-third of those clinical strains were correctly identified as E. coli while half of those were correctly reported as Klebsiella. In addition to it, some of the DFI strains were also identified as Enterobacter, Yersinia, Acinetobacter, and as well as some unknown bacterial genera. These results were confirmed initially by biochemical tests followed by API20E and 16s rRNA sequencing. Finally, through antibiogram we also observed that the reconfirmed E. coli and Klebsiella strains were resistant to various antibiotics, such as ampicillin, cefotaxime, ciprofloxacin, azithromycin etc. Conclusions: Our findings allude to the fact that diagnostics facilities though are able to identify gram-negative bacteria within clinical strains, they are unable to identify the causative agents properly. We also hypothesize that misidentification of bacterial pathogens may promote the dissemination of antibiotic resistance.

Background: Emergence of multi-drug resistant pathogens has afflicted the population of developing countries like Bangladesh in recent years for which a sustainable holistic combating approach is required. Since Streptomyces is a source of numerous bioactive molecules, the study was aimed at physico-chemical characterization of 8 indigenous Streptomyces isolates of Bangladesh. Methods: Tolerance of Streptomyces isolates to different growth conditions was assessed at temperature range 4 °C to 60 °C, pH range 3 to 11 and salinity up to 15% of NaCl concentration. Ability of isolates in utilizing different carbohydrates was checked through media of single sugar as sole carbon and energy source. The antimicrobial activity of the isolates against four pathogens was assayed with culture supernatant obtained from 5 different pH levels. The data was analyzed statistically by software R version 3.4.1. Results: All the isolates grew optimally in the temperature range of 20- 40 °C, pH range of 5- 9 and salinity of 1% NaCl concentration although certain isolates tolerated up to 60 °C and 10% of salinity. Based on the sugar profiles, the isolates were allocated into different biotypes and their relatedness was found with S. mutabilis (Ca), S. subrutilis(Cb1) and S. mirabilis (Cb2) as positioned at same clusters in the dendrogram. The antimicrobial molecules produced by the Streptomyces isolates were not heat stable and denatured by ethanol, hence presumed as protein. The maximum antagonism was recorded against E. coli by isolate B-5 at pH 6 (18 mm), against S. typhimurium by A- 9 at pH 9 (20 mm), against S. aureus by B-7 at pH 5 (18 mm) and against B. cereus by B- 7 at pH 8 and 9 (18 mm) as well as by D-5 at pH 7 (18 mm). It was also deduced that the pH as a growth condition significantly influenced the production of pathogen specific antimicrobial compounds by the Streptomyces isolates. Conclusion: The ability of the Streptomyces isolates in tolerating wide range of growth conditions would be of special advantage and the influence of pH in pathogen specific antimicrobial production could enhance the chances of obtaining diverse antimicrobials.