EXPERIMENT: 1
AIM: To prepare 100 ml of 0.1M NaOH (Sodium hydroxide) solution.
MATERIALS REQUIRED: NaOH, beaker, distilled water, measuring cylinder, stirrer, weighing machine, paper.
THEORY: NaOH is an organic compound aka caustic soda. It has Na+ as cationic part and OH− as anionic part. At ambient ordinary temperature this alkali decomposes protein causing severe burns. It is highly soluble in water and absorbs moisture and carbon dioxide from air. In many industries pulp and paper, textiles, drinking water, soaps and detergents are manufactured using NaOH and also used as a drain cleaner with wide range of applications.
CALCULATION:
Molarity = Number of moles of substance 1 litre of solution
1.1 = w/m 1 litre
= w/40 1 litre w = 4 gm 4 gm for 1000 ml X gm for 100 ml = 0.4 gm
PROCEDURE: Weigh 0.4 gm of NaOH using weighing machine. Add 100ml of distilled water to the beaker. Add NaOH to it and stir it using the stirrer.
PRECAUTIONS: Weigh the distilled water and NaOH accurately. Use gloves while weighing the organic compound to prevent injuries.
EXPERIMENT: 2
AIM: To prepare and autoclave 100 ml of agar media.
MATERIALS REQUIRED: Beaker, distilled water, stirrer, measuring cylinder, weighing machine.
COMPONENTS OF AGAR MEDIA:
➢ Peptone 0.5gm
➢ Beef extract 0.3gm
➢ NaCl 0.5gm
➢ Agar powder 2gm
THEORY: Nutrient agar media is used to facilitate the growth of the wide range of non-fastidious bacteria.
0.5% Peptone - provide organic nitrogen
0.3% beef extract/yeast extract - the water-soluble content of these contribute vitamins, carbohydrates, nitrogen, and salts
1.5% agar - this gives the mixture solidity
0.5% Sodium Chloride - this gives the mixture proportions similar to those found in the cytoplasm of most organisms
Distilled water - water serves as a transport medium for the agar's various substances
pH
In the beginning of lab, we were advised to obtain a nutrient agar petri plate, which is used for the cultivation of microbes supporting growth of non-fastidious organisms. Since it contains many nutrients, a wide variety of bacteria and fungi can grow. Taking the plate,
(Biology Dept.). 0.1 ml of E.coli K or 0.1ml of E.coli B was added to the 10 fold dilution. Using soft agar technique, the growth media mixture with E.coli was plated and incubated.
|MSA Agar |For organisms that are |Isolates for mannitol fermentation |Yellow color change in |Staphylococcus aureus |
For the temperature test each bacteria was placed on a nutrient agar and incubated for either 10, 20, 30, 40, or 50 degrees Celsius for 48 hours. During the pH test, each organism was placed on four agars varying in pH level from pH 2, 4, 6 and 8 and incubated near 37 degrees Celsius for 48 hours. For the osmotic pressure test, each organism was placed on four agars one each containing 2%, 5%, 8%, and 11% NaCl concentration levels. These were incubated near 37 degrees Celsius for 48 hours. The results of the tests are recorded in Tables 1, 2, and 3. All tests were performed according to the instructions provided in Leboffe & Pierce(1). The biochemical tests used on both unknowns and the ubiquity are:
(Harley, 2011, pp. 102-103) Sucrose and lactose serve as a fermentable carbohydrate sources which promote its growth of fecal forms and provide color change differentiation. (Harley, 2011, p. 104) Therefore, if E. coli is being platted on the EMB, after plate’s incubation period, it should produce a green metallic sheen on the agar due to the bacteria being a strong fermenter. My unknown bacteria tested positive for growth, and agar was fermented reddish burgundy in color. Subsequently, the unknown bacteria was later inoculated with a sterilized loop into the liquid tryptic soy broth and incubated at an appropriate temperature. Its results were used for proper identification of turbidity, spots and flocculation. (BD™ Tryptic Soy Broth (TSB), 2008) The results of the unknown were cloudiness and some settlement on the bottom of the tryptic soy liquid. The next step was conducted to find out if all the bacteria, as well as the unknown culture, required oxygen for growth, varying from an aerobic environment, where bacteria needs oxygen to grow, to facultative anaerobic environment, where bacteria will grow either with or without oxygen but better in its presence. All the bacteria, along with the unknown, were separately inoculated and tested. My unknown culture results tested positive for growth in facultative anaerobic environment. In the next sequence of lab experiments, the results of unknown bacteria were determined by glucose fermentation,
The next day an orange goopy textured product resulted. The extracts were then dried and combined with anhydrous sodium sulfate, then evaporated with dry air under the hood in a warm water bath. The liquid was cooled and had an initial weighing of 0.5887g. It was reweighed several minutes later with a final
Bacteria are small, unicellular prokaryotic microbes. They have many morphologies, which include rod-shaped, spherical, spirals, helices, stars, cubes, and clubs. Classification of bacteria begins with either aerobic (requiring diatomic oxygen for growth) or anaerobic (not requiring O2 for growth). Bacteria can simply be narrowed down to gram positive (organism that stains purple or blue by Gram stain) or gram negative (organism that stains red or pink by Gram stain). Many physical and nutritional factors influence bacterial growth. Physical factors include temperature (psychrophiles, thermophiles, and mesophiles), pH (neutrophiles, acidophiles, and alkalinophiles), O2 concentration (aerobic
a. Aqueous Sodium Hydroxide—NaOH (aq) is a very strong base, which will completely disassociate into Na+ and OH- ions, which would make it a very strong electrolyte. Chemical reaction of the disassociation of Sodium Hydroxide: NaOH (aq)Na+ (aq)+ OH-(aq)
that the bacteria are capable of growing on the agar and that there was nothing
The goal of this lab was to make a NaCl^ solution and calculate its molarity so that students can become acquainted with “volumetric glassware, the balances and quantitative transferring of liquids.” 25 mL of NaCl solution was completely transferred with AgNO_3 solution test and the molarities of the original 25 mL and diluted 250 mL solutions were calculated.
Sodium metal is extremely reactive in comparison to hydrogen due to its ranking in the activity series, and when combined with water, it would displace one of the hydrogens in a water molecule, forming NaOH, also known as sodium hydroxide (Beran, 2014). This compound is known to be basic because it can donate a hydroxide ion, and all basic substances turn litmus paper blue (Beran, 2014).
Experiment to investigate the amount of sodium hydroxide needed to neutralize the solution of vinegar
For citrate utilization part, the Simmon’s citrate agar was inoculated with bacteria A and B and incubated for 24 hours. After 24 hours, Simmon’s citrate agar for bacteria A remains green which was a negative reaction. For bacteria B, the colour change from green to blue which was a positive reaction. The positive reaction indicates the bacteria uses citrate as carbon source while negative reaction indicates the bacteria unable to utilize citrate as carbon source. The pH indicator was bromothylmol blue which detect the change of the colour of the agar. Yellow colour indicates acidic pH , green indicates neutral pH and blue indicates alkaline pH. The growth of bacteria on the agar as well as the production of bicarbonates, ammonia and ammonium
HCl is known as Hydrogen chloride in its gas state, but when in the presence of water, it is known as hydrochloric acid(PubChem). Hydrochloric acid is extremely corrosive and has uses in both laboratories and industrial settings(PubChem). This acid can cause short term complications such as irritation to the eyes and nose or it can leave long term effects like dermatitis and chronic bronchitis (PubChem). Sodium hydroxide is a base that neutralizes acids and when in liquid form it has a higher density than water (PubChem). The compound is used in various textile industries (PubChem). NaOH can be corrosive to metals and is toxic if ingested (PubChem).
Six experiments were carried in this report concerning the effect that different environmental factors have on microbial growth. The results were recorded into tables where (+) symbolises growth and (–) symbolises no growth.