Gram-Negative Bacteria Water Activity PDF

Why gram-negative bacteria require higher aw?? 1. Gram-negative bacteria have an outer membrane composed of lipopolysaccharides, which is not present in Gram-positive bacteria. This outer membrane acts as a barrier that restricts the passage of molecules and nutrients, including water...

Why gram-negative bacteria require higher aw?? 1. Gram-negative bacteria have an outer membrane composed of lipopolysaccharides, which is not present in Gram-positive bacteria. This outer membrane acts as a barrier that restricts the passage of molecules and nutrients, including water, into the cell. Therefore, Gram-negative bacteria generally require a higher water activity than Gram-positive bacteria to grow and survive because they need more water to penetrate this barrier and access the nutrients and other molecules they need. 2. Gram-negative bacteria have a thinner peptidoglycan layer in their cell wall compared to Gram-positive bacteria. This makes them more susceptible to osmotic stress, which can result from low water activity environments. Therefore, Gram-negative bacteria may require higher water activity levels to avoid osmotic stress and maintain cellular integrity.