How does the branching of hydrocarbon chain of synthetic detergents affect their biodegradability ?

Explanation

Detergents having highly branched hydrocarbon chains cause pollution in rivers. The reason being that side chains stop bacteria from attacking and breaking the chains.
Thus, lesser the branching more is the biodegradability i.e., detergents with long straight hydrocarbon chains are more easily degraded than those having branched hydrocarbon chains.

Since unbranched (i.e., straight) chains are more prone to attack by bacteria, therefore in most of the detergents used these days, the breaching is kept to be minimum, so that the detergents become easily biodegradable.