D3.10 Sequences of identified butyric acid bacteria

Main Objectives

The main objective is development and optimization of a production process for butyric acid from crude glycerol based on Mixed Microbial Culture (MMC) biotechnology. This includes analyses of the composition and development of microbial populations of the MMC during fermentations. The current delivery characterizes the microbial composition of the MMC in general and the butyric acid bacteria in particular. The microbial composition were monitored by Next Generation Sequencing.

 Main Outcomes

Next Generation Sequencing was used as a tool to monitor changes in the microbial composition during fermentations. Changes in the microbial communities at different stages of the fermentations (different transfers) have been monitored by next Generation Sequencing techniques based on DNA sequencing technologies primarily targeting the 16S rDNA region.

For the activated sludge samples, the dominating bacteria in all samples belonged to the phylum Firmicutes in particular the classes Clostridia and Bacilli as well as Gammaproteobacteria. Among the most dominating genera were known glycerol consumers like Clostridium, Klebsiella and Escherichia.

For the anaerobic sludge the dominating genera in the batch test (enriched hexane pretreated crude glycerol) were Clostridium and Klebsiella together with unclassified genera belonging to Proteobacteria while enriched untreated glycerol in fed-batch was dominated by the genus Blautia followed by Clostridia and unclassified genera belonging to Firmicutes.

Both the genera Clostridium and Blautia includes species typical associated with butyric acid production. Species like C. tyrobutyricum, C. butyricum and B. coccoides (reclassified from C. coccoides) are identified in samples from MMC fermentations.

The sulfate reducing bacteria in the inoculum from the anaerobic sludge was diverse, however all genera appeared at very low frequencies all below the cut-off of 1 %. The kinetic control seemed to control the SRBs while the absence of kinetic control allowed for the growth of SRBs leading to the problems relating to the production of H2S.


  • Review of technical glycerol potential from biodiesel production and availability for improved cascading in Europe

    May 2, 2017

    The article entitled: “Review of technical glycerol potential from biodiesel production and availability for improved cascading in Europe” has been published and is available online. Authors: André Brosowski (DBFZ), Stephanie Hauschild (DBFZ), Karin Naumann (DBFZ), Jens Hösel (DBFZ), Daniela Thrän (Helmholtz Centre for environmental research), Type of publication: Article – Research Paper Date: April 2017 Publication: […]


  • 42M Progress Meeting – April 26 to 28, 2017 – Leipzig (Germany)

    April 11, 2017

    All the project partners will be hosted by DBFZ in Leipzig (Germany) from April 26 to 28, 2017. This is a good opportuny to discuss about the project advancement after the last Consortium Meeting which took place from October 12 to 14, 2016 in Hurtigruten, Bergen – Trondheim, Norway. Agenda available here: GRAIL_42M_Agenda     […]


  • GRAIL e-NEWSLETTER #5 – February 2017

    February 22, 2017

    PROJECT SUMMARY GRAIL : GLYCEROL BIOREFINERY APPROACH FOR THE PRODUCTION OF HIGH QUALITY PRODUCTS OF INDUSTRIAL VALUE GRAIL is a 48-months collaborative project funded by the European Commission, under the FP7 Programme for Knowledge Based Bio-Economy. The topic of GRAIL project is “Preventing and valorizing bio-waste in biorefineries optimal and cost-effective industrial biocatalysts”. What’s inside […]


  • D2-2 – Operating parameters for batch experiments

    January 5, 2017

    Main Objectives To provide information about operational parameters at batch configurations such as, the effect of inoculum, addition of nutrients, pH control and substrate concentration to improve hydrogen and ethanol production  Main Outcomes According to the results, the selected inoculum was sludge from an aerobic wastewater treatment plant and an aerobic pretreatment. Also, it was […]