Answer: They require light
Step-by-step explanation:
The bacteria such as Pseudomonas is gram negative, rod shaped, bacterium which has an extraordinary nutritional versatility.
These bacteria is obligate respirer, which uses aerobic respiration as its optional metabolism. They can also respire anerobically by the help of the nitrate or other alternative. In this case the electron acceptor is not cytochrome oxidase.
The can respire without oxygen, but this process does not yields much ATP as like that of oxygen dependent respiration.