BISC209: Recipes

From OpenWetWare
Jump to navigationJump to search
Wellesley College-BISC 209 Microbiology -Spring 2010


Misc Recipes for test media and their reagents

Lab 4

PEA MEDIUM
  • 10g tryptose
    3g Beef extract
    5g Sodium Chloride
    2.5g Phenylethyl alcohol
    15g Agar to 1 liter distilled or deionized water
    pH 7.1-7.5.
EMB medium
  • 10g peptone
    10g Lactose
    2g dipotassium phosphate
    0.4g eosin Y
    0.065 g methylene blue
    15 g Agar
    final pH 6.9-7.3

Lab 5
catalase test
fresh hydrogen peroxide

Oxidase test
order fresh commercial kits
positive controls: Bacillus spp, Neisseria, Micrococcus or Pseudomonas

OF-glucose medium
0.2 per cent peptone
0.5 per cent NaCl
0.03 per cent K2HPO4
0.3 per cent agar
0.003 per cent bromthymol blue
1.0 per cent carbohydrate
pH 7.1.


cellulose degradation medium
(use melted agar of the appropiate enrichment media choices
or try Nutrient agar for all???

starch medium
3 g Beef extract
10 g soluble starch
12 g agar
bring up to 1 liter with distilled or deionized water
pH 7.3-7.7

Ammonification reagent
Nesler's reagent will be purchased commercially. Please be extremely careful handling this solution.

  • Recipe: 0.09 mol/L solution of potassium tetraiodomercurate(II) (K2[HgI4]) in 2.5 mol/L potassium hydroxide. A yellow coloration indicates the presence of ammonia: at higher concentrations, a brown precipitate may form. The sensitivity as a spot test is about 0.3 μg NH3 in 2 μL.
    NH4+ + 2[HgI4]2− + 4OH− → HgO·Hg(NH2)I + 7I− + 3H2O
    It is toxic if swallowed, inhaled or absorbed through the skin. It presents a neurological hazard and may act as a carcinogen and be a reproductive hazard. It is corrosive and causes burns. Wear gloves and consider performing this assay in a hood.

Lab 6

MRVPMethyl red test
  • dextrose peptone broth
    0.7% peptone,
    0.5% dextrose
    0.5% dipotassium phosphate
    pH 6.7-7.1
Methyl red Reagent
  • 0.1 methyl red dye
    ethanol 00 ml
    distilled water to 500 ml
VP Reagent A
  • 5 g alpha naphthol
    bring volume to 100 ml absolute alcohol
VP Reagent B
  • 40g potassium hydroxide
    bring to volume with 100 ml distilled water


SIM agar and Reagent recipes:
  • < Approximate Formula* Per Liter
    Pancreatic Digest of Casein - 20.0 g
    Peptic Digest of Animal Tissue - 6.1 g
    Ferrous Ammonium Sulfate - 0.2 g
    Sodium Thiosulfate - 0.2 g
    Agar - 3.5 g
  • Kovac's reagent: (per liter)
    p-Dimethylaminobenzaldehyde 50,0g
    Amyl Alcohol 750.0 ml
    Hydrochloric acid 250.0 ml
  • Indole Spot Test Reagent
    p-Dimethylaminocinnamaldehyde 10.0 g
    Hydrochloric acid 100.0ml
    Water, deionized 900.0 ml

General Recipe for Carbohydrate fermentation
This medium is available commercially

  • Purple broth base (1% peptone, 0.1% beef extract, 0.5% NaCl, 20 µg/ml bromcresol purple) plus 1% of the desired carbohydrate.

Links to Labs

Lab 1
Lab 2
Lab 3
Lab 4
Lab 5
Lab 6
Lab 7
Lab 8
Lab 9
Lab 10
Lab11
Lab 12