tryptic soy broth tryptic soy broth tryptic soy broth or trypticase soy broth (frequently abbreviated as tsb) is used in microbiology laboratories as a culture broth to grow aerobic bacteria. it is a complex, general purpose medium that is routinely used to grow certain pathogenic bacteria, which tend to have high nutritional requirements (i.e., they are fastidious). its agar counterpart is tryptic soy agar (tsa). one of the components of tryptic soy broth is phytone archived 2014-08-22 at the wayback machine, which is an enzymatic digest of soybean meal. tsb is frequently used in commercial diagnostics in conjunction with the additive sodium thioglycolate which promotes growth of anaerobes. preparation to prepare 1 liter of tsb, the following ingredients are dissolved under gentle heat. adjustments to ph should be made using 1n hcl or 1n naoh to reach a final target ph of 7.3 ± 0.2 at 25 °c (77 °f). the solution is then autoclaved for 15 minutes at 121 °c (250 °f). 17 grams (0.60 oz) of trypticase peptone (tryptone) 3 grams (0.11 oz) of phytone peptone (soytone) 5 grams (0.18 oz) of sodium chloride (nacl) 2.5 grams (0.088 oz) of dipotassium phosphate (k2hpo4) 2.5 grams (0.088 oz) of dextrose (glucose) 1 liter (35 imp fl oz; 34 u.s. fl oz) with distilled water