Production of chondroitin sulfate (I) comprises hydrolyzing bovine or porcine cartilage with Bacillus licheniformis alkaline protease, thermolyzing the enzyme by heating in an acid medium, concentrating (I) by ultrafiltration and dialysis, and precipitating (I) by adding ethanol. Independent claims are also included for: (1) use of peptones obtained as by-products from the above process to produce culture media； (2) use of amino acids obtained as by-products from the above process to produce pharmaceutical, cosmetic or dietetic products.
