Laboratory Practice Record 2023-03-18 14:30-17:30

1. Prepare 1mol/L ammonium acetate solution

• Weigh 77.08g ammonium acetate solid (volatile)

• Add 400mL of water to completely dissolve

• Pour the liquid into a 1L volumetric flask

• Rinse the beaker used for dissolution 7 times with distilled water

• Add volumetric flask to the mark and seal with parafilm

• Stir well

Experimental operation introduction page Prepared ammonium acetate solution

2. Prepare 10mol/L sodium hydroxide solution

• Weigh 400g of sodium hydroxide solid (dangerous, should be handled with gloves)

• Add 500mL of water to completely dissolve and return to room temperature

• Pour the liquid into a 1L volumetric flask

• Rinse the beaker used for dissolution 7 times with distilled water

• Add volumetric flask to the mark and seal with parafilm

1. Stir evenly

Undissolved sodium hydroxide solution

3. Prepare solid medium

Experimental purpose: To study the effect of riboflavin (vitamin B2) concentration on the growth of Mortierella fungus

Preparation: Prepare solid culture medium

Data collection: The molar mass of riboflavin is 376.37g/mol

Mother liquor preparation: 10mL of 0.1mol/L riboflavin solution

-Weigh 3.76g riboflavin

• Add 8mL water to dissolve

• Add 2mL of dilute sodium hydroxide solution to accelerate dissolution

• After dissolving, it becomes a dark yellow solution

Concentration gradient: 10-3, 10-4, 10-5, 10-6, 10-7mol/L

Quantitative calculation: C1V1=C2V2

A draft of the calculation

Concentration mol/L	/(control group)	10-3	10-4	10-5	10-6	10-7
Amount of mother solution added	/	1mL	0.1mL	0.01mL	0.001mL	10mL of 10-6 solution

The volume of mother solution required at 10-7mol/L is less than the minimum range of the pipette, so use a 10-6mol/L solution to dilute it ten times.

Prepare a total of 600mL of culture medium

• Cut raw potatoes over 120g

• Wash, peel and chop into small pieces

• Add more than 600mL of water to the pot to boil the rotten potatoes

• Add 120g glucose powder and dissolve

• Filter with gauze and pour into a large beaker (plastic)

• Use a measuring cylinder to take 100mL of medium liquid into a total of 6 Erlenmeyer flasks

• Add the previously calculated amount of riboflavin separately

• Add 1.00g of agar powder to form a solid medium

• Seal and add to autoclave at 121 degrees Celsius for 20 minutes