Assessing the Biological Inhibitors Effect on Crude Oil Wax Appearance Temperature Reduction

To assess the effect of micro-organisms on the reduction of wax appearance temperature (WAT) of waxy crude oil, some appropriate strains were obtained from contaminated samples exposed to hydrocarbon compounds for a long time. By conducting some screening tests, four strains were chosen and aerated in a bioreactor; they were then grown in some hydrocarbon environments in order to produce biological inhibitors. The ability of the biological inhibitors in wax deposition prevention or reduction of WAT is assessed. The WAT is determined by means of the optical absorption spectroscopy method. The absorption plots show that biological compounds are highly effective in reducing WAT; however, different strains are not of the same efficiency. In some cases, the efficiency of biological inhibitors is more than chemical inhibitors. The optimization experiments were run with the objective of achieving the maximum WAT reduction through the Taguchi design method, and the optimum cultivation condition was identified. According to the analysis of variance, pH with a contribution of 49.63% is the most influential factor on the cultivation of the most efficient micro-organisms. The factors of temperature, the inoculation fluid, and nitrogen concentrations are ranked after pH with the contributions of 32.39, 7.92, and 1.39% respectively

Probiotics and Prebiotics in medicine and dentistry

Probiotics are live micro-organisms that if are consumed in sufficient numbers, will been beneficial effects on the health of their host. Probiotics have inhibitori effects on the pathogenic bacteria and the expression of their virulence gene. Studies have shown that probiotic bacteria reduce chronic inflammation of the bowel disease, prevention and treatment of diarrhea disease, necrotizing enterocolitis, urinary tract infection and infections are caused by Helicobacter pylori. Lactic acid bacteria can settle site of adhesin of pathogenic bacteria in the gastrointestinal tract and prevent them. Also produce antimicrobial factors such as bacteriocins, organic acids and biosurfactant. Today, researchers use probiotics to prevent and remove biofilms for example L.plantarum has inhibitori effect on the production molecular signals, homoserine lactone and elastase production in P. aeruginosa. Different strains of Lactobacillus inhibited swarming and urease activity of Proteus. Also have been proven inhibitori effect of bacteriocin of L. plantarum on biofilm formation and antibiotic resistance of S. marcescens. It has been found effect of biosurfactant of L. acidophilus on S. mutans biofilm formation. Prebiotics are indigestible nutrition that caused increase the number and activity of limeted bacteria in the colon. A prebiotic must improve growth of Bifidobacterium and lactic acid bacteria and can be increase antimicrobial activity of probiotics. At the result can say that probiotic bacteria use for treatment pathogenic bacteria with antibiotics or their prebiotics and they inhibitori expression of virulence genes by defferent mechanism and metabolite

Introduce of Viable But Nonculturable Bacteria

Viable-But-Nonculturable-State (VBNC) is the condition in which bacteria fail to grow on their routine bacteriological media where they would normally grow and develop into colonies, but are still alive and capable of renewed metabolic activity. VBNC state is useful for evaluating public health and for ascertaining the sterility of drinking water, pharmaceuticals, and foodstuff. A number of bacteria, mostly pathogenic to humans, have been proved to enter into this state in response to natural stresses such as starvation, incubation out of optimum growth temperature, increased osmotic pressure, etc. Once in the VBNC state, they undergo various physiological, structural, and genetic alterations. These alterations result in reduced cell size, conversion from bacilli to coccid, thickened cell walls, and peptidoglycan gaining many cross links. Metabolic changes also occur that include reductions in growth, nutrient transport, and respiratory rate; biosynthesis of new protein, and ATP remaining at a constant level. It has been shown that in the VBNC state, some pathogens conserve their virulence properties. Gene expression continues in the VBNC cell. Nucleic acids remain intact in the early VBNC phase but they gradually undergo degradation with prolonged VBNC. Cytological methods such as direct viable count and reduction of tetrazolium salts, and molecular methods such as reverse transcription polymerase chain reaction and green fluorescent protein have been used for the study of VBNC. Resuscitation from VBNC state starts when the inducing factor(s) is/are lifted. Factors that help the resuscitation of VBNC bacteria include addition of certain nutrients and chemicals, introduction of a few culturable cells into the VBNC cell population, and passage through the animal host. As virulence properties are sustained during the VBNC phase, special care must be paid when evaluating sterility of drinking water

Study of a Mathematical Model of Biocide Effect on a Biofilm Isolated from a Cooling System Using the Microtiter Plate

Bacterial colonization on metal surfaces and their metabolic activities lead to biocorrosion. In fact, any agent removing the biofilm or decreasing its thickness is capable of preventing biocorrosion. Biocides make up one such agent. These agents can control bacterial biofilms, remove these structures, or kill cells within them. The object of this research is to study the thermodynamic model of biocide penetration into the biofilm using the microtiter plate test. First, the biofilm bacteria were isolated to form a mix- bacterial biofilm. The biocide effect on the mix-biofilm was then determined using the microtiter plate test. Results from this test were compared with those from a thermodynamic model and it was revealed that the effects of oxidizing biocides such as sodium hypochlorite and hydrogen peroxide are in good agreement with the results from the model. The results indicated that increased biocide concentration leads to the removal of the biofilm or to the kill-off of the cells within it. However, in the case of non-oxidizing biocides such as sulfathiazol, glutaraldehyde, and alkyl dimethyl ammonium chloride, the efficiency results did not agree well with the results from the thermodynamic model such that increased biocide concentration did not remove the biofilm nor did it kill off the cells within i

The Effect of Prebiotic Chitosan on the growth and antimicrobial characteristic of Probiotic lactobacilli

Background and Aim: Nowadays, prebiotics are the matter of interest, because of stimulating the growth and activity of beneficial enteric bacteria (probiotic) and their antimicrobial and antitumor characteristics. The aim of this research is to study the effect of prebiotic Chitosan on the growth of probiotic bacteria and their antimicrobial effect. Materials and Methods: This research was done in 2010 in order to study of the effect of prebiotic chitosan on the growth of probiotic bacteria Lactobacillus acidophilus PTCC 1643 and Lactobacillus casei PTCC 1608 by using of drawing growth curve of these bacteria in the presence of different chitosan concentrations, also, the effect of this prebiotic on antimicrobial properties of probiotic bacteria was investigated against Escherichia coli by using of overlay method and blank disk method. Results: According to the test results, the growth of two probiotic bacteria were increased in the presence of chitosan and the most effective concentration of prebiotic chitosan was achieved, 6.5 (mg/mL).Antimicrobial effects of probiotic bacteria were increased in the presence of chitosan against E.coli especially Entrohaemoragic E. coli in comparison with the time that probiotic bacteria were used alone. Conclusions: According to the results of this study, prebiotic chitosan, due to increasing effect on the growth and antimicrobial characteristic of probiotic lactobacillus, can be a proper candidate for effective symbiotic compound against pathogenic bacteria

Study of antagonistic effects of Lactobacillus strains as probiotics on multi drug resistant (MDR) bacteria isolated from urinary tract infections (UTIs)

Objective(s):Urinary tract infection (UTI) caused by bacteria is one of the most frequent infections in human population. Inappropriate use of antibiotics, often leads to appearance of drug resistance in bacteria. However, use of probiotic bacteria has been suggested as a partial replacement. This study was aimed to assess the antagonistic effects of Lactobacillus standard strains against bacteria isolated from UTI infections. Materials and Methods: Among 600 samples; those with ≥10,000 cfu/ml were selected as UTI positive samples. Enterococcus sp., Klebsiella pneumoniae, Enterobacter sp., and Escherichia coli were found the most prevalent UTI causative agents. All isolates were screened for multi drug resistance and subjected to the antimicrobial effects of three Lactobacillus strains by using microplate technique and the MICs amounts were determined. In order to verify the origin of antibiotic resistance of isolates, plasmid curing using ethidium bromide and acridine orange was carried out. Results: No antagonistic activity in Lactobacilli suspension was detected against test on Enterococcus and Enterobacter strains and K. pneumoniae, which were resistant to most antibiotics. However, an inhibitory effect was observed for E. coli which were resistant to 8-9 antibiotics. In addition, L. casei was determined to be the most effective probiotic. Results from replica plating suggested one of the plasmids could be related to the gene responsible for ampicillin resistance. Conclusion: Treatment of E. coli with probiotic suspension was not effective on inhibition of the plasmid carrying hypothetical ampicillin resistant gene. Moreover, the plasmid profiles obtained from probiotic-treated isolates were identical to untreated isolates