A research team of the department of Biology from University of Rome Tor Vergata developed a pioneeristic technology to make the production of microalgae more efficient and sustainable. Through the use of controlled, low power, ultrasounds, a new SonoPhotoBioreactor (S-PBR) has been perfected, able to stimulate the algae, increasing its biomass and, in some cases, doubling the quantity of valuable molecules.
The study has been recently published on Bioresource Technology, edited by Elsevier: https://doi.org/10.1016/j.biortech.2025.132810
Microalgae are among the most promising resources for the future bioeconomy: they can produce biofuels, animal feed, cosmetics and high-value compounds for the food and pharmaceutical industries. On the other side, its colture on a large scale had to face issues such high costs and complex procedures. The challenge is to optimize the production in a sustainable way.
The solution presented by the innovative startup Yeastime (born on 2021) and developed by the University of Rome Tor Vergata’s research team coordinated by Roberta Congestri associate professor and Blasco Morozzo della Rocca, PhD – both committed at department of Biology of the University – overtakes the current use of ultrasounds, especially in terms of control and replicability.
Their bioreactor, with the addition of ultrasound and light, in fact, became an S-PBR sono-photo-bioreactor, a modular, precise system characterized both computationally and experimentally to irradiate microalgae cultures with specific doses of acoustic energy.
This process was tested on two microalgae of commercial interest: Chlorella vulgaris and Desmodesmus sp. The first one is already approved for human food use with a high protein content. The second is characterized by high resistance to stressful conditions and could be an alternative for producing biomass in climates and conditions prohibitive for other algae.
The results were surprising: in Desmodesmus sp. an intermediate density treatment doubled the protein content, from 20 percent to 40 percent of the biomass dry weight. In Chlorella vulgaris, the same treatment more than doubled the carbohydrate content (from 9 percent to 19 percent). A maximum intensity irradiation, on the other hand, promoted an overall increase in biomass produced for both species, up to 30 percent more than in untreated controls.
Federico Ortenzi, biotechnologist at Yeastime, PhD at Rome Tor Vergata and first author of the publication a explains “This technology represents a crucial step forward for the bioeconomy. It allows us to “talk” with the microalgae in a new way, guiding their metabolism towards the production of the compounds we are interested in, without causing chemical or light stress, with significant amount of energy saved and greater sustainability of the process. Moreover, the “plug-and-play” design of the device makes it easy to integrate into existing photobioreactors, facilitating its transfer to industrial scale and we are working in synergy with the University of Rome Tor Vergata”.
