title: Using enriched cultures for elevation of anaerobic syntrophic interactions between acetogens and methanogens in a high-load continuous digester.
abstract: Volatile fatty acids (VFAs) are key intermediates in anaerobic digestion. Enriched acetogenic and methanogenic cultures were used for syntrophic anaerobic digestion of VFAs in a high-load continuous reactor fed with acetic (HAc), propionic (HPr) and butyric (HBu) acids at maximum concentrations of 5, 3 and 4 g/L, respectively. Interactive effects of HPr, HBu and HAc were analyzed. Furthermore, hydraulic retention time (HRT) and methanogen to acetogen population ratio (M/A) were investigated as key microbiological and operating variables of VFA anaerobic degradations. Optimum conditions were found to be HPr=1125.0mg/L, HBu=1833.4 mg/L, HAc=1727.4 mg/L, HRT=21 h and M/A=2.5 (corresponding to maximum VFA removal and biogas production rate (BPR)). Results of verification experiments and predicted values from fitted correlations were in close agreement at 95% confidence interval. HRT and M/A had positive effects on VFA removal and BPR. M/A was the most important factor that affected BPR. All VFAs inhibited VFA removals.
authors.affiliation: Biotechnology Group, Chemical Engineering Department, Faculty of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran, Iran.
authors.forename: T
authors.initials: T
authors.lastname: Amani
authors.forename: M
authors.initials: M
authors.lastname: Nosrati
authors.forename: S M
authors.initials: SM
authors.lastname: Mousavi
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000143:Acids / Q000737:chemistry*; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D020148:Butyric Acid / Q000737:chemistry; D004867:Equipment Design; D005232:Fatty Acids, Volatile / Q000737:chemistry; D005740:Gases; D008697:Methane / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013816:Thermodynamics; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification
chemical_list: D000143:Acids; D005232:Fatty Acids, Volatile; D005740:Gases; D011422:Propionates; D012722:Sewage; D020148:Butyric Acid; C029658:propionic acid; D008697:Methane; D019342:Acetic Acid