Complex sentence: Iron is not usually readily available in the environment this group of bacteria find themselves in, but because iron is essential in sustaining life, due to its role as co-enzymes in respiration and DNA synthesis, bacteria must adapt to have a mechanism for intake of iron.
Split into simpler sentences: Iron is not usually readily available in the environment this group of bacteria find themselves in. However iron is essential in sustaining life due to its role in co-enzymes in respiration and DNA synthesis, so bacteria must adapt to have a mechanism for intake of iron.