Chitin Magnetic Beads are nano-superparamagnetic beads covalently coupled with chitin. With a fast magnetic response rate, high protein binding capacity and low non-specific binding, Chitin Magnetic Beads provide a rapid and efficient method to purify CBD (chitin-binding domain)-fusion proteins from cell culture supernatant. The beads are simply added to cell culture supernatant and CBD-fusion proteins will bind to the beads. After washing unbound proteins off, the CBD-fusion proteins can be eluted from the magnetic beads or the protein-bound magnetic beads can be directly used in downstream experiments (e.g. capturing target proteins, which bind to the immobilized CBD-fusion proteins, from crude cell lysates). The process can be completed manually or fully automated for high throughput applications.