Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2006
Publication Date: July 13, 2006
Citation: Somkuti, G.A., Gilbreth, S.H., Steinberg, D.H. 2006. Production of the bacteriocin thermophilin 110 in whey-based media. (abstract). National Meeting of the American Dairy Science Association. Paper No. T59. Journal of Dairy Science 89 (Suppl.1): 180. Technical Abstract: Thermophilin 110 is a bacteriocin of the dairy bacterium Streptococcus thermophilus with a high level of activity against pediococci that cause spoilage in wine and beer fermentations. Whey-based media were evaluated to establish optimum conditions for producing thermophilin 110 on a larger scale. Whey permeate solids were reconstituted to 3 per cent lactose concentration, and the effects of yeast extract and the nontoxic organic buffer salts MOPS, MES and PIPES were tested on the growth of S. thermophilus ST110, changes in medium pH and thermophilin 110 accumulation over a period of 24 h. The presence of 0.5% yeast extract was essential for thermophilin 110 production which paralleled growth of S. thermophilus ST110 at 37uC and reached the highest level after 10-12 h, followed by a gradual decline, as shown by bioassays with Pediococcus acidilactici as the target organism. The presence of organic buffer salts decreased the rate of decline in medium pH and generally resulted in increased dry cell mass (ug/ml) and higher levels of thermophilin 110 (units/ug of cells) produced. The greatest effect was shown by the addition of 1% MES to the medium which reduced pH drop to 1.8 units after 10 h (compared to 2.3 pH units in the control), and resulted in a 1.5-fold increase in cell mass (495 ug/ml) and a 7-fold increase in thermophilin 110 production (77 units/ug of dry cells) over the control. Further, the productivity of S. thermophilus ST110 after 10 h in the whey permeate medium was 10-fold higher than in conventional tryptone-yeast extract-lactose medium (7.8 thermophilin 110 units/ug of dry cells). The results showed that the use of whey-permeate based media may offer an economical approach to producing larger quantities of thermophilin 110 that could find applications in controlling spoilage pediococci in wine and beer fermentations.