Chloroform ensures proper extraction of substances typically found in MIPs that are difficult to break and interfere with gDNA extraction.
Chloroform (CHCl3) or trichloromethane is a nonpolar (hydrophobic) solvent, in which nonpolar proteins and lipids get dissolved to promote the partitioning of lipids and cellular debris into the organic phase, leaving isolated DNA protected in the aqueous phase. Chloroform ensures phase separation of the two liquids because it has a higher density (1.47 g/cm3) and forces a sharper separation of the organic and aqueous phases, thereby assisting in the removal of the aqueous phase with minimal cross contamination from the organic phase (Heikrujam J. et al. 2020). Chloroform is volatile in nature and it does not hinder the downstream process.
References
Jina Heikrujam, Rajkumar Kishor and Pranab Behari Mazumder (May 19th 2020). The Chemistry Behind Plant DNA Isolation Protocols, Biochemical Analysis Tools - Methods for Bio-Molecules Studies, Oana-Maria Boldura, Cornel Baltă and Nasser Sayed Awwad, IntechOpen, DOI: 10.5772/intechopen.92206. Available from: https://www.intechopen.com/chapters/72074