Commercial phycocyanin extraction is energy-intensive and lacks scalability. Alternatively, this study reports the systematic investigation of hydrodynamic cavitation for intensified phycocyanin extraction from Spirulina. Additionally, biomethane potential of the residual biomass, obtained after phycocyanin extraction was also investigated. The biomethane generation rate decreased with an increasing number of passes while the biomethane potential remained unaffected. To reliably compare phycocyanin extraction across systems, dimensionless normalised yields were defined. A normalised phycocyanin yield of 4.3 (52 mg phycocyanin g