Question 20N.3.HL.TZ0.b
| Date | November 2020 | Marks available | [Maximum mark: 1] | Reference code | 20N.3.HL.TZ0.b |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | b | Adapted from | N/A |
Citric acid was produced in a fermenter using the pulp of cassava (Manihot esculenta) and the fungus Aspergillus niger. This process was carried out at room temperature for 6 days and citric acid was then collected. The apparatus was cleaned and set up for a new fermentation. The process is shown in the diagram.
[Source: Prado, F.C., Vandenberghe, L.P.S., Woiciechowski, A.L., Rodrígues-León, J.A. and Soccol,
C.R., 2005. Citric acid production by solid-state fermentation on a semi-pilot scale using different percentages of
treated cassava bagasse. Brazilian Journal of Chemical Engineering, 22(4), pp.547–555.]
Suggest, with a reason, whether this is a batch or a continuous fermentation.
[1]
batch fermentation because the citric acid is collected at the end of the fermentation
OR
batch fermentation because the process was carried out over 6 days then re-set up
OR
diagram does not show constant supply of nutrients so it must be a batch;
Most suggested that it was a batch fermentation, but some omitted to provide a reason; a few others had incorrect answers.
