Temperature On The Growth And Survival Of Bacteria Biology Essay

Temperature On The Growth And Survival Of Bacteria Biology EssayAbstract The aim of this try out was to asses the process and survival of 5 bacteria. The method involved placing each of the bacteria in water baths of various temperatures for certain periods of time, taking them out and placing them in their optimum temperatures and monitoring their harvest-feast/survival rate over the course of the week. The results obtained showed that how surface the bacteria grew after they had been placed in their optimum temperatures and left for a week. From this it was think what the temperature class of each bacteria was.Introduction The objective of the experiment was to look at the growth and survival rate of 5 bacteria namely, vitamin B complex stearothermophilus, Escherichia coli, Enterococcus faecalis, Bacillus subtilis and genus Pseudomonas fluorescens. Escherichia coli, commonly referred to as E.coli is a gram negative bacterium which is rod shaped.It is usu tout ensembley frame in the large intestine of warm red-blooded animals. It is also prime in foods and water. It is a facultative aerobe meaning that O2 is not necessarily required for growth but is preferred for better growth thence it is able to metabolise both aerobic and anaerobicall(a)y. Every microorganism has a minimal, optimal and maximal temperature. These be known as cardinal temperatures and they tell us a lot about the nature of a microorganism. A mesophile is an organism which grows at its surpass in medium temperature conditions. A psychrophile on the other go is an organism which is capable of growing in extremely cold temperatures. Thermophiles are virtually the opposite of psychrophiles. Theyre organisms which are capable of growing and reproducing the hot environments. The term thermophile room that it is heat loving or heat tolerant.The temperature and pH are good indicators of the environment E.coli can be found. The fact that it has a ph of 6-7 means that it is found in mi ldly acidic to neutral places which explains why it is in the large intestine of mammals. The bacteria manage to survive in these various environments due to their adaptative metabolism. (Madigan, Martinko, Dunlap and Clark, 2008).Enterococcus faecalis (E.faecalis) is a gram positive and is naturally occurring in the intestine of mammals, the soil, in plants and in water. The presence of E.faecalis and E.coli in the water is usually an indication that the water has been contaminated. It is found in similar habitats to E.coli.Bacillus stearothermophilus (B.stearothermophilus) is also a rod shaped gram positive organism it is usually found in hot springs and the soil.Pseudomonas fluorescens (P.fluorescens) is a gram negative rod shaped bacterium. It is usually found in cooler environments such as water. It is an obligate aerobe which means that it cannot grow in the absence of oxygen. Bacillus subtilis (B.subtilis) is also a rod shaped gram positive bacterium which is mainly found in the soil. It too is an obligate aerobe (Brooker, Widmaier, whole meal flour and stilling, 2007).Method Please refer to the schedule for this.ResultsBelow are the tabulated results that were obtained from the experiment. duck 1 shows the effect of inoculating the bacteria at different temperatures had on their growth rate. Table 2 shows the results of exposing the bacteria to extreme heat conditions on their survival rate.Temp (C)25374255E.coli+++++++++++++++++++++++++++++++++E.farcalis+++++++++++++++++++++++++++++++++B.subtilis++++++++++++++++++++++++++++++++P.flourescence++++++++++++++B.steaothermophilus++++++++++++The table above shows how well the bacteria grew at different temperatures. Really strong growth is represented by +++, medium by ++, slow growth by + and no growth by -. Looking at E.coli for example it is clear that it only grows well in the region of 25-42C anything beyond this showed absolutely no growth occurring. metre (minutes)E.coliTemp (C)025309040Y, N, YY, Y , YY, Y, YY, Y, YY, Y, Y60Y, Y, YY, Y, YY, Y, YN, N, NN, N, N80N, Y, YN, N, NN, N, NN, N, NN, N, N100N, N, YN, N, NN, N, NN, N, NN, N, NB.subtilis40Y, YY, YY, YY, YY, Y60Y, YY, YY, YY, YY, Y80Y, YY, YY, YY, YY, Y100Y, YY, YY, YY, YY, NTable 2 The effect of heat on survival of bacteria. Key Y= growth present N= no growthE.faecalis40YYYYY60YYYYN80YYYNN100YYYNNB.stearothermophilus40Y, NY, NY, NN, NN,N60Y, NN, NN, NN, NN, N80N, NN, NN, NN, NN, N100N, NN, NN, NN, NN, NP. fluorescens40Y, N, YY, Y, YY, Y, YY, Y, YY, Y, Y60Y, Y, YY, Y, YY, Y, YN, N, NN, N, N80N,Y, YN, N, NN, N, NN, N, NN, N, N100N,Y,NN, N, NN, N, NN, N, NN, N, NDiscussionWith the breeding that is in table 1 the nature of each bacterium can be established. E.coli showed exceptionally strong growth in the range of 25 to 42C. These results are perfectly in line with the characteristics of a mesophile as such it is safe to assume that E.coli is a mesophile. This also explains why it is found in the human beings intestine. The core temperature of the human body is 36.8C 0.7 which according to the literature is the optimal temperature of E.coli. The same thing goes for E.faecalis. It too is a mesophile and one of the locations where it is found is also the GI tract. The information in table 1 coupled with the fact that it is found in the same location as E.coli means that it too has the same optimal temperature as E.coli.B.subtilis grew throughout all the temperature ranges but grew the exceed in 55C. It was however strange to see it grow in the areas of 25-37C as it is by nature a Thermophile. The minimum temperature that is required for thermophiles to grow is approximately 42C. B.stearothermophilus on the other hand showed a classic example of a thermophillic bacterium. It grew best at 55C. The last bacterium in table 1 was P. Fluorescens. It grew well at 25C but seemed to be decreasing mollify substantially at 37C. The information on the table did not quiet fit in with the characteristics which ar e exerted by mesophiles. Mesophiles usually grow best at around 30-40C however P.fluorescens optimal temperature was around 25C which meant that it could not be a psychrophile. It did however fit the characteristics of a psychrotroph. Psychrotrophs are organism which grow at 0C i.e. similar to psychrophiles but, usually have an optimum temperature of 25C whereas psychrophiles have and optimum temperature of 10-12C (www1).Table 2 showed the effects of exposing the bacteria to high temperatures had on their survival. Temperature is most likely the most important factor that contributes to the growth and survival of the bacteria. From the literature it can be gathered depending on the organism, exposing it to very high temperatures will kill it. In the case of E.coli this is the case. It managed to stay alive at 40C for 90minutes. This is understandable as this is below its maximal temperature. Once it had been placed into higher temperatures for a long enough duration, it died off. Th is was not the case for B.subtilis. It proved to be growing throughout all temperature ranges for the full 90 minutes of the experiment. The fact that it managed to survive at temperatures as high as 100C implies that it may be a hyperthermophile (Madigan, Martinko, Dunlap and Clark, 2008).P. fluorescens also died off after being exposed to increased temperatures for some time. At 30 and 90 minutes, all of people who were doing the experiment reported that there were no bacteria alive at 60C. At 2 minutes into the experiment at 80 and 100C none of the bacteria were alive. nigh of the results obtained from the experiment seemed to be in line with the information found in the literature some werent for example E.faecalis was still alive in almost all of the higher temperature ranges when clearly it shouldnt have been as it was is a mesophile and shouldnt grow after around 46C. B.stearothermophilus, a thermophile was not growing in temperature ranges where it should have been. These m istakes may have been due to applied correct aseptic techniques while inoculating properly. In order to eliminate such errors the experiment could be run 2 to 3 times.