title: High organic loading rate on thermophilic hydrogen production and metagenomic study at an anaerobic packed-bed reactor treating a residual liquid stream of a Brazilian biorefinery.
abstract: This study evaluated the influence of a high organic loading rate (OLR) on thermophilic hydrogen production at an up-flow anaerobic packed-bed reactor (APBR) treating a residual liquid stream of a Brazilian biorefinery. The APBR, filled with low-density polyethylene, was operated at an OLR of 84.2 kg-COD m(-3) d(-1). This value was determined in a previous study. The maximum values of hydrogen production and yield were 5,252.6 mL-H2 d(-1) and 3.7 mol-H2 mol(-1)(total carbohydrates), respectively. However, whereas the OLR remained constant, the specific organic load rate (sOLR) decreased throughout operation from 1.38 to 0.72 g-Total carbohydratesg-VS(-1) h(-1), this decrease negatively affected hydrogen production. A sOLR of 0.98 g-Total carbohydratesg-VS(-1) h(-1) was optimal for hydrogen production. The microbial community was studied using 454-pyrosequencing analysis. Organisms belonging to the genera Caloramator, Clostridium, Megasphaera, Oxobacter, Thermoanaerobacterium, and Thermohydrogenium were detected in samples taken from the reactor at operation days 30 and 60, suggesting that these organisms contribute to hydrogen production.
authors: CTBE: Brazilian Bioethanol Science and Technology Laboratory - CNPEM, Rua Giuseppe Máximo Scolfaro, 10.000 Bairro Guará, Barão Geraldo, 13.083-970 Campinas, SP, Brazil; Biological Processes Laboratory, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP), Engenharia Ambiental - Bloco 4-F, Av. João Dagnone, 1100 - Santa Angelina, 13.563-120 São Carlos, SP, Brazil. Electronic address: djalma.ferraz@bioetanol.org.br.
authors: Antônio Djalma Nunes
authors: ADN
authors: Ferraz Júnior
authors: Laboratorio de Ecología Microbiana, Instituto de Investigaciones Biológicas Clemente Estable, Av. Italia 3318, Montevideo, Uruguay. Electronic address: cetchebehere@iibce.edu.uy.
authors: Claudia
authors: C
authors: Etchebehere
authors: Biological Processes Laboratory, Center for Research, Development and Innovation in Environmental Engineering, São Carlos School of Engineering (EESC), University of São Paulo (USP), Engenharia Ambiental - Bloco 4-F, Av. João Dagnone, 1100 - Santa Angelina, 13.563-120 São Carlos, SP, Brazil. Electronic address: zaiat@sc.usp.br.
authors: Marcelo
authors: M
authors: Zaiat
mesh_terms: D000693:Anaerobiosis / Q000502:physiology*; D019149:Bioreactors / Q000382:microbiology*; D001938:Brazil; D006859:Hydrogen / Q000378:metabolism; D056186:Metagenomics / Q000379:methods; D020959:Polyethylene / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*; D046950:Thermoanaerobacterium / Q000502:physiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage; D006859:Hydrogen; D020959:Polyethylene
keywords: 454-Pyrosequencing; Anaerobic process; Bio-hydrogen; Sugarcane vinasse; Thermophilic