  We showed in our previous studies that just $3\%$ cross-links, at special
points along the contour of the bacterial DNA help the DNA-polymer to get
organized at micron length scales \cite{jpcm,epl}.
  In this work, we investigate how does the release of topological constraints
help in the organization of the DNA-polymer. Furthermore, we show that the
chain compaction induced by the crowded environment in the bacterial cytoplasm
contributes to the organization of the DNA-polymer. We model the DNA chain as a
flexible bead-spring ring polymer, where each bead represents $1000$ base
pairs. The specific positions of the cross-links have been taken from the
experimental contact maps of the bacteria {\em C. crescentus} and {\em E.
coli}. We introduce different extents of topological constraints in our model
by systematically changing the diameter of the monomer bead. It varies from the
value where the chain crossing can occur freely to the value where the chain
crossing is disallowed. We also study the role of molecular crowders by
introducing an effective Lennard Jones attraction between the monomers. Using
Monte-Carlo simulations, we show that the release of topological constraints
and the crowding environment play a crucial role to obtain a unique
organization of the polymer.
