BD Accuri News

Ramón Mira de Orduña on Wine Microbiology

Ramón Mira de Orduña is professor of enology at the École d'Ingénieurs de Changins in Switzerland. His research in enology focuses on wine analysis and microbiology, especially the nutrition and physiology of wine lactic acid bacteria and yeast. Dr. Mira de Orduña described his method of automating and controlling fed-batch fermentations, which was developed while he was at Cornell University, and told us what surprised him on the day he installed the BD Accuri™ C6 flow cytometer.

Q: Would you tell us about your research program?

Dr. Mira de Orduña: My overall research program focuses on microbial physiology in enology. Specifically, I study the metabolism of wine-related strains of yeast and bacteria in response to nutritional, fermentation, and enological parameters. Our goal is to address current and future winemaking challenges such as climate change, and to improve winemaking methods with regard to final wine composition, aroma, and process sustainability (such as utilization of energy).

Q: How do you use the BD Accuri C6 in your research?

Dr. Mira de Orduña: The inoculation size, the microbial population, and microbial activity are all essential for the progress and success of fermentations. We use the BD Accuri C6 to assess microbial counts (titer) and viability. By using propidium iodide (PI) and thiazole orange (TO) to differentiate live vs dead organisms, we can rapidly assess the effect of fermentation conditions on the activity of production organisms.

Q: Tell us about your automated fed-batch system.

Dr. Mira de Orduña: Using FT-NIR (Fourier Transform Near-Infrared) technology, the system is able to determine sugar concentrations during fermentations in real time. Integrated with control modules and pumps, this allows us to carry out automated continuous fed-batch fermentations where substrate concentrations are kept constant and low in order to reduce osmotic stress in production organisms. This avoids fermentation problems and improves production efficiency.

The BD Accuri C6 allows us to monitor and control the process by providing rapid results on yeast titer and viability. Currently, the flow cytometry data is obtained offline; that is, samples are taken manually and analyzed on the BD Accuri C6. The next automation step will be to integrate the flow cytometer with an automated sampling device. This will allow us to obtain yeast viability data inline, which can then be used to automatically adjust the sugar concentrations during fermentations.

Q: Why did you choose the BD Accuri C6? What surprised you about it?

Dr. Mira de Orduña: We chose the BD Accuri C6 because of its good ratio of performance, flexibility, and cost. The methodological flexibility provided by the number of lasers and detectors was important to us, since it ensures our ability to apply future methods.

We were highly surprised by the ease of implementation of the equipment and methods. Running an analytical laboratory, we are used to a significant lag-time—from installation of new infrastructure to acquisition of useful data—for technologies such as liquid/gas chromatography and FT-NIR. When we get new equipment, it typically takes days if not weeks to fully understand the software and obtain useful data. With the BD Accuri C6, we were able to obtain useful yeast numbers and viability data on the day of the installation. Our automation projects would not have been possible without the rapid and reliable data provided by the flow cytometer.

Read the July 2013 BD Accuri™ News feature on automating personal flow cytometry »

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