Collection and phylogenetic characterization of bacterial consortium used in batch anaerobic reactor applied to hydrogen production

Author(s)

Sandra Imaculada Maintinguer

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD)
• Defense date: 2009-03-20

Examining board members

Maria Bernadete Amâncio Varesche Silva; Claudia Etchebehere Arenas; Eugenio Foresti; Valéria Maia de Oliveira; Isabel Kimiko Sakamoto

• Advisor: Maria Bernadete Amâncio Varesche Silva

Abstract

The heat treatment of the inoculum associated with the pH control has been applied to select hydrogen-producing bacteria such as Clostridium sp. Therefore, this study aimed at preserving and keeping the anaerobic bacteria cultures producing hydrogen that comes from the granular sludge in UASB reactor, used to treat waste from pig farming, after heat treatment. For this, heat treatment of the inoculum was done and later, enrichment with serial dilutions to get anaerobic consortium. The 20% (v/v) of the bacterial consortium was used in essays for determination of hydrogen gas in reactors with different concentrations of sucrose and xylose. The reactors (2 L), fed with sucrose and xylose, separately, in triplicate, to 37 Celsius degrees, pH 5.5 and headspace with \'HE\' (100%) for the conditions: (1) 630.0 mg sucrose/L, (2) 1184.0 mg sucrose/L, (3) 1816.0 mg sucrose/L, (4) 4128.0 mg sucrose/L, (5) 630.0 mg xylose/L, (6) 1341.0 mg xylose /L, (7) 1848.0 mg xylose/L and (8) 3588.0 mg xylose/L. \'H IND.2\' production was detected in all the anaerobic reactors and there was no methane generation. \'H IND.2\' yield for the conditions (1), (2), (3), (4), (5), (6), (7) and (8) were, respectively, 15% (1, 2 mol \'H IND.2\'/mol sucrose), 20% (1.6 mol \'H IND.2\'/mol sucrose), 15% (1.2 mol \'H IND.2\'/mol sucrose), 4% (0.3 mol \'H IND.2\'/mol sucrose), 3.0% (0.2 mol \'H IND.2\'/mol xylose), 8.0% (0.5 mol \'H IND.2\'/mol xylose), 10.0% (0.6 mol \'H IND.2\'/mol xylose), and 14% (0.8 mol \'H IND.2\'/mol xylose). The metabolic intermediarie products were acetic, butyric acid and ethanol in all anaerobic reactors. The main morphology was Gram positive bacilli and endospores formers. The cloning and sequencing analysis of the bacterial consortium revealed the presence of Clostridium genus (57%), Burkolderia genus (30%), Klebsiella genus (8%) and uncultivated bacteria (5%). The hydrogen gas production was due to bacterial consortium that were present in the studied conditions, marked mainly by species Clostridium sp., Clostridium acidotolerans and Klebsiella pneumoniae, recognized as \'H IND.2\' and volatile acids producing. (AU)