Cooperative interactions within a marine bacterial dual species biofilm growing on a natural biodegradable substratum

Pseudoalteromonas sp. S91 is a marine bacterium known to secrete chitinases and proteases, hydrolytic enzymes responsible for the degradation of chitin and protein, respectively, which enable access to nutrients contained in chitinous materials such as squid pen. In a dual species biofilm grown on squid pen, Pseudoalteromonas sp. S91 was able to support the accumulation of Vibrio sp. S141, which is unable to degrade squid pen but able to metabolise the chitin subunit N'-acetylglucosamine (GlcNAc), a product of squid pen hydrolysis. When grown on a glass substratum in the presence of a soluble carbon source that only Pseudoalteromonas sp. S91 could use, its biofilm provided no support to Vibrio sp. S141.