Unit 4: Production and Formulation of Biopesticides - Practice Quiz

1 What is the main purpose of mass production of a microbial biopesticide?

2 Which condition is most important for maintaining a pure microbial culture?

3 What is a culture medium?

4 Which nutrient is commonly included in a microbial growth medium?

5 What is inoculation in microbial production?

6 Why is pH monitored during microbial cultivation?

7 What is the role of aeration in the production of many microbial biopesticides?

8 Which instrument is commonly used to observe microbial growth on solid media?

9 Why is the incubation temperature important in microbial production?

10 What is contamination in a microbial culture?

11 What is the main purpose of formulating a microbial biopesticide?

12 What is a carrier in a microbial biopesticide formulation?

13 Which is an example of a solid carrier used in microbial formulations?

14 Which type of formulation contains water as its main medium?

15 Why should a formulation protect microbial cells from drying?

16 What does viability refer to in a microbial biopesticide?

17 What is the function of a stabilizer in a microbial formulation?

18 Why is uniform mixing important during formulation?

19 Which factor commonly reduces the shelf life of a microbial biopesticide?

20 What is the purpose of packaging a microbial biopesticide in a sealed container?

21 A laboratory must inoculate a 100 L fermenter with Bacillus subtilis while minimizing the lag phase. Which inoculum strategy is most appropriate?

22 A fungal biopesticide produces abundant aerial conidia on moist cereal grains but few conidia in liquid broth. Which production method should be selected?

23 A plate inoculated with 0.1 mL of a dilution develops 80 colonies. What was the viable count of the original bacterial culture?

24 During submerged production of a shear-sensitive fungal biopesticide, dissolved oxygen falls below the desired level. What should be tried first?

25 A team plans to mass-produce a baculovirus biopesticide in a standard nutrient broth without host cells. Why is this approach unsuitable?

26 A sugar-rich fermentation medium becomes dark and inhibitory after autoclaving. Which modification is most appropriate?

27 The objective is to obtain a stable, endospore-rich biomass of Bacillus for formulation. When should the culture generally be harvested?

28 A fermenter sample shows the expected colony type plus colonies with a different color and margin. What is the best immediate response?

29 A bacterial biopesticide grows well in a 2 L fermenter but poorly after scale-up to 200 L because oxygen transfer is inadequate. Which parameter is most useful for guiding scale-up?

30 Persistent foam develops during aerobic fermentation and threatens to block the exhaust filter. Which control measure is most suitable?

31 A fungal conidial product must be diluted in water and applied using a conventional sprayer. Which formulation is most appropriate?

32 A wettable powder floats on water and forms persistent clumps during preparation of the spray suspension. Which component should be adjusted first?

33 A sterile carrier is mixed with fungal biomass at a ratio of one part biomass to four parts carrier. If the biomass contains CFU/g, what is the expected final concentration?

34 After fungal conidia are mixed with a talc carrier, the viable count drops sharply even before storage. What is the most likely carrier-related cause?

35 A heat-sensitive fungal biopesticide loses viability during drying at . Which change is most appropriate?

36 Conidia in a foliar biopesticide rapidly lose activity after exposure to sunlight. Which additive would most directly improve protection?

37 A dry microbial formulation gains moisture during storage and its viable count declines. Which packaging change is most appropriate?

38 A grower wants to tank-mix a Trichoderma formulation with a fungicide. What should be done before recommending the mixture?

39 An antagonist must be delivered gradually into the soil near developing roots. Which formulation type best fits this purpose?

40 Two formulations contain the same initial viable count, but their storage stability must be compared. Which experimental design provides the most useful evidence?

41 During scale-up of an aerobic bacterial biopesticide, biomass yield falls despite maintaining the same agitation speed and aeration rate per vessel volume. Dissolved oxygen approaches zero during exponential growth. Which scale-up criterion most directly addresses the limitation?

42 A sterilized bacterial fermentation remains contamination-free for 12 hours but shows a second bacterial morphotype immediately after the first antifoam addition. A retained broth sample collected before that addition is pure. What is the most probable contamination route?

43 A production fermenter inoculated with a stationary-phase culture shows a long lag, variable final biomass, and delayed metabolite production. Which modification is most likely to improve batch-to-batch consistency?

44 A solid-state fungal culture uses 10 kg of completely dry cereal substrate. How much water must be added to obtain 60% moisture on a wet-weight basis, assuming no water loss during mixing?

45 For mass production of a Bacillus-based biopesticide intended to contain stable endospores, which harvest strategy is most appropriate?

46 An 8 L culture contains CFU/mL. Downstream recovery preserves 60% of viable cells, and the recovered material is incorporated into 1.2 kg of product. What is the expected viable count?

47 Two Bacillus thuringiensis batches have equal viable counts and similar sporulation percentages, but one provides substantially lower insect mortality. Which quality-control test best resolves whether the difference concerns biological potency?

48 A team proposes producing a baculovirus biopesticide in the same cell-free fermenter used for bacterial biopesticides. What is the fundamental flaw in this proposal?

49 High initial glucose in a bacterial biopesticide fermentation causes acetate accumulation, oxygen demand spikes, and reduced product formation. Which process change most directly addresses all three effects?

50 A technician plates 0.1 mL of a dilution and counts 84 colonies. Assuming each colony arose from one culturable unit and the dilution was prepared correctly, what was the original concentration?

51 A wettable-powder formulation retains acceptable viability immediately after processing but cakes and loses viability during humid storage. Which intervention most directly addresses the shared cause?

52 A microbial wettable powder wets completely within 20 seconds but forms a dense sediment soon after dilution, producing nonuniform spray delivery. Which reformulation is most appropriate?

53 Fungal conidia remain viable in an oil dispersion during storage but lose germinability immediately after the formulation is diluted in water. Which experiment best identifies the responsible formulation component?

54 A bacterial biopesticide loses 95% of its viable count within one hour when tank-mixed with a copper fungicide, although each product is stable alone. What is the most defensible application recommendation?

55 A formulation begins with CFU/g and follows , where month. If the minimum specification is CFU/g, what is the longest whole-month shelf life that does not exceed the modelled limit?

56 A carrier is sterile immediately after autoclaving, but formulated batches repeatedly contain environmental bacteria. Contamination is absent when the carrier is sampled before cooling and blending. Which control point should be investigated first?

57 A microbial granule disintegrates rapidly after placement in dry soil, but the organism establishes poorly around the granule. Which formulation change most directly improves the local establishment environment?

58 A foliar microbial formulation is effective in the laboratory but rapidly loses activity under sunlight. Which development strategy best tests a formulation-based solution?

59 Microscopy indicates cells/g in a formulated bacterial product, whereas plate counting indicates only CFU/g. Which additional observation most specifically supports cell death rather than cell aggregation as the explanation?

60 Five kilograms of microbial concentrate contains CFU/g. Blending and drying retain 80% of the viable cells. How much sterile carrier must be added to obtain a final product containing CFU/g?