In March, I visited Raul Muñoz and his Gas Treatment and Microalgae research group in Valladolid Spain. The intention was to learn about their work in microalgal cultivation on waste gases from an engineering point of view. I was blown away by the kindness and generosity of the lab group who gave their time to explain their projects and let me shadow sampling and analysis.
On the first day I met with the principal investigator, Raul Munoz, who gave me a tour of the facilities, a brief overview of some of the projects and introduced me to members of the group. I was immediately impressed by the scale at which they were working, my experience with low volume benchtop experiments looked pretty meagre in comparision to the 100-200 L tubular photobioractor and high rate algal pond (HRAP) experiments they were running in the lab. I was inspired by the fact that their work is being scale up to an industrial level, through European initiatives Urbiofin and Incover.
Raul’s lab group are currently mainly focusing on refining biogas from fermentation using microbes to remove impurities, and accumulation of polyhydroxyalkanoate (PHA) and polyhydroxybutyrate, which can be extracted from the biomass for making bioplastics. Some of the projects involving biogas upgrade included pressurised anaerobic digestion with H2 injection; BTEX removal for PHA accumulation; ectoine production; siloxane removal; PHA, protein and enzyme production from algae grown in swine manure waste water.
The first person I shadowed was Roxana, who took me through routine gas and liquid sampling of her 120 L photobioreactor. I was inspired by her incredibly organised method for monitoring mass balance of the system through gas and liquid analysis, and the watertight system (excuse the pun) which had obtained fantastic data supported by comprehensive metadata. I particularly appreciated being taught about the little solutions she had found while trouble-shooting her set up, such as using little pieces of plastic whizzing round the system to reduce fouling, and using a vertical column for improved gas transfer.
Yadira was the second person who I shadowed. We did some gas sampling and she talked me through how her system with PHA accumulating methanotrophs worked. Like Sara she had set up a recirculating gas system to improve mass transfer, something which I am trying to incorporate into my set up.
Charli also allowed me to shadow her. She was cultivating a Scenedesmus consortia in a HRAP connected to a vertical column for absorption of biogas. Judit and Ana were then extracting the lipids and proteins to look for viable products with industrial applications. It was also exciting to hear about a pilot scaled up version which she had recently returned from.
The group were also beginning to expand into the molecular biological side of these engineering focused project. Elisa and Sergio discussed their work on genetically engineering improved hydroxyectoine and PHB accumulation. Visiting professor Alejandra Martinez also delivered an excellent seminar about her previous work on enzyme production in bacteria involved in lignocellulosic fermentation.
The main thing which I took away from the visit was learning about different kinds of bioreactor systems and receiving advice on what to think about and what to avoid. Raquel Lebrero was particularly helpful for this. I had read a few of her previous papers so I had many questions about problems she may have encountered when using alternative systems such as biotrickling filters, flat membranes and multiple phase combined systems to improve VOC removal. I’m so grateful for the generosity of everyone in the group, it was an educational and inspiring trip from which I hope there will be some exciting collaborations.