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DatoValore
TitleEFFECT OF PERIODIC FEEDING ON SUBSTRATE UPTAKE AND STORAGE RATES BY A PURE CULTURE OF THIOTHRIX (CT3 STRAIN)
AbstractA pure culture of Thiothrix strain CT3 has been aerobically cultured under periodic acetate feeding in a Sequencing Batch Reactor (SBR) at volumetric organic load rate of 0.12gCODL1 d1. Two different culture residence times (12 d or 20 d) were adopted as well as two different feed frequencies (1 and 4 d1, for each culture residence time), the volumetric organic load rate being the same under all conditions. The transient response of the microorganism to the periodic acetate feed was investigated through batch tests with biomass withdrawn from the SBR, as function of the different SBR operating conditions. In all tested conditions, a quick transient response to the acetate spike was observed with fast increase of acetate uptake rate (ranging from 71 to 247mgCODgCOD1h1). This transient response was mainly due to acetate storage in form of poly-hydroxybutyrate (ranging from 45% to 64% of the observed yield) whereas the growth response (i.e. increase of production rate of active biomass) generally played a minor role (ranging from 21% to 38% of the observed yield). Apart from this general trend, culture residence time as well as feed frequency had a strong impact on transient behaviour of cultured cells. The overall transient response (i.e. maximum specific substrate removal rate) increased as culture residence time decreased or as feed frequency increased. Moreover, the ratio of storage response and growth response increased as the overall transient response decreased, i.e. the storage response was preferentially maintained when cells presented a lower transient response. The ability of the cells to increase their growth rate with respect to SBR average value was the lowest under the most unfavourable conditions (residence time 20 d, feed frequency 1 d1) and increased with the increase in maximum substrate uptake rate.
SourceWater research (Oxf.) 41 (1), pp. 177–187
KeywordsThiothrix CT3PHB storageTransient conditionsSequencing batch reactor
JournalWater research (Oxf.)
EditorPergamon Press., New York, Regno Unito
Year2007
TypeArticolo in rivista
DOI10.1016/j.watres.2006.09.002
AuthorsMAJONE M. (a); BECCARI M. (a); DIONISI D. (a); LEVANTESI C. (b); RAMADORI R. (b); TANDOI V. (b)
Text42140 2007 10.1016/j.watres.2006.09.002 ISI Web of Science WOS 000243692100023 Thiothrix CT3 PHB storage Transient conditions Sequencing batch reactor EFFECT OF PERIODIC FEEDING ON SUBSTRATE UPTAKE AND STORAGE RATES BY A PURE CULTURE OF THIOTHRIX CT3 STRAIN MAJONE M. a ; BECCARI M. a ; DIONISI D. a ; LEVANTESI C. b ; RAMADORI R. b ; TANDOI V. b a Department of Chemistry, University La Sapienza , P.le Aldo Moro 5, 00185 Rome, Italy; b Water Research Institute, National Research Council IRSA CNR , via Reno 1, 00198, Rome, Italy A pure culture of Thiothrix strain CT3 has been aerobically cultured under periodic acetate feeding in a Sequencing Batch Reactor SBR at volumetric organic load rate of 0.12gCODL1 d1. Two different culture residence times 12 d or 20 d were adopted as well as two different feed frequencies 1 and 4 d1, for each culture residence time , the volumetric organic load rate being the same under all conditions. The transient response of the microorganism to the periodic acetate feed was investigated through batch tests with biomass withdrawn from the SBR, as function of the different SBR operating conditions. In all tested conditions, a quick transient response to the acetate spike was observed with fast increase of acetate uptake rate ranging from 71 to 247mgCODgCOD1h1 . This transient response was mainly due to acetate storage in form of poly hydroxybutyrate ranging from 45% to 64% of the observed yield whereas the growth response i.e. increase of production rate of active biomass generally played a minor role ranging from 21% to 38% of the observed yield . Apart from this general trend, culture residence time as well as feed frequency had a strong impact on transient behaviour of cultured cells. The overall transient response i.e. maximum specific substrate removal rate increased as culture residence time decreased or as feed frequency increased. Moreover, the ratio of storage response and growth response increased as the overall transient response decreased, i.e. the storage response was preferentially maintained when cells presented a lower transient response. The ability of the cells to increase their growth rate with respect to SBR average value was the lowest under the most unfavourable conditions residence time 20 d, feed frequency 1 d1 and increased with the increase in maximum substrate uptake rate. 41 Effect of periodic feeding on substrate uptake and storage rates by a pure culture of Thiothrix CT3 strain 3_CT3_2007_Water_Rese.pdf Articolo in rivista Pergamon Press. 0043 1354 Water research Oxf. Water research Oxf. Water res. Oxf. Water research. Oxf. caterina.levantesi LEVANTESI CATERINA roberto.ramadori RAMADORI ROBERTO valter.tandoi TANDOI VALTER TA.P07.002.002 Sviluppo di nuovi processi di controllo dell inquinamento idrico.