This organism could be a chemosynthetic organism. These organisms perform the process chemosynthesis where one or more carbon molecules and nutrients into organic matter by oxidation of inorganic compounds. Hope this answers the question.
Since the bacteria derives energy from chemical compounds rather than from Sun, it is a chemotroph. Chemotrophs are the organisms that derive energy from chemical compounds.
Since the bacteria uses sulfur as fuel, it is chemolithotroph. Chemolithotrophs are the organisms that cannot fix carbon dioxide as the phototrophs do and use any inorganic compound.
The paramecium have a higher chance of survival when grown separately. Besides the chart, we can assume that the reason this is possible is that they have easier access to more resources, like food and water.
