Analysis

Citric acid Analysis


Citric acid was analysed, using pyridine–acetic anhydride method as reported by Marrier and Boulet (1958). One ml of the diluted culture filtrate along with 1.30 ml of pyridine was added in the test tube and swirled briskly. Then 5.70 ml of acetic anhydride was added in the test tube. The test tube was placed in a water bath at 32 ± 0.25 °C for 30 min. The optical density was measured on a spectrophotometer (405 nm) and citric acid contents of the sample were estimated by comparing it with standerds (run parallel, replacing 1.0 ml of the culture filtrate with distilled water).

Composition of Medium For optimization of pH for SSF of molasses using corn cobs as carrier substrate for citric acid production by A. niger
 
Substrate corn cobs
S.no Substrate (g) 10%molasses solution (ml) pH


1 5 15 3

2 5 15 4

3 5 15 5

4 5 15 6

5 5 15 7


Composition of mdium for optimization of inoculum size for citric acid production by A. niger in SSF of molasses medium.
 
Substrate corn cobs
 
S.no Substrate (g) 10%molasses solution (ml) pH Inoculum size


(ml)

1             5          15             6                                 3

2 5 15 6 4

3 5 15 6 5

4 5 15 6 6

5 5 15 6 7

Composition of medium for optimization of temperature


Composition of medium for optimization of nitrogen sources

Substrate corn cobs


S.no

Nitrogen Sources w/w 1%

1 Ammonium sulphate

2 Corn steep liqour

3 Urea

4 Peptone

5 Yeast extract


PH, 6


Inoculum size, 5ml.

Temperature, 35oC.









Substrate corn cobs

S.no pH Inoculum size (ml) Temprature oC








1                 6              3           25

2              6            4                30

3 6 5 35

4 6 6 40

5 6 7 45