title: Effect of aeration and agitation on growth rate of Thermus thermophilus in batch mode.
abstract: The growth kinetics of Thermus thermophilus HB27 was investigated in rich medium (Thermus medium) under batch cultivation at 65 degrees C in 3-l fermentors. The growth and oxygen consumption rates were highly dependent on the aeration and agitation rates. Volumetric mass transfer coefficient (K(L)a, h(-1)) and hence oxygen transfer rate (OTR, mol m (-3) h(-1)) into the fermentation broth increased with increased aeration and/or agitation rates. A K(L)a and OTR of 175.4 h(-1) and 31.7 mol m(-3)h(-1) respectively, corresponding to 500 rpm agitation and 2 vvm aeration with a mixture of air and oxygen, were required to avoid oxygen limitation. The maximum growth rate (mu(max), h(-1)), doubling time (t(D), h), and dry cell weight determined for T. thermophilus HB27 growing under these conditions were 0.27 h(-1), 2.67 h, and 3g/l respectively. This cell yield is higher than any previously published reports for growth of Thermus cultures, including studies that employed pressurized bioreactors.
authors.affiliation: Illinois Institute of Technology, Chemical and Environmental Engineering Department, Chicago, IL 60616, USA.
authors.forename: Meltem U
authors.initials: MU
authors.lastname: Demirtas
authors.forename: Arati
authors.initials: A
authors.lastname: Kolhatkar
authors.forename: John J
authors.initials: JJ
authors.lastname: Kilbane