Groundbreaking in wastewater treatment research, Osaka Metropolitan University scientists were able to claim that the union of yeast and green algae is an effective means to improve performance in the process. This new idea might cut energy consumed to treat wastewater through this traditional practice whose method requires electricity input into wastewater to provide oxygen and feed bacteria and other microorganisms to break down contaminants. Photosynthesis will obviously produce oxygen with green alga. However, the alga does not fare well in conditions of low carbon dioxide concentration, meaning it has practical use in very limited ways.
The answer lies in a familiar microorganism that has held center stage in both bakeries and wineries—the yeast. Among the yeasts, the most potent carbon dioxide producer, Saccharomyces cerevisiae, has come out as the perfect complement to green alga for the treatment of wastewater. The researchers-much like a lab scientist seeking an elixir-were asking under the guidance of Associate Professor Ryosuke Yamada of the Graduate School of Engineering: Under what conditions of microorganism combination is the best pair formed to achieve most efficient purification of wastewater? Their results show that adding yeast aids in the uptake of ammonia and phosphate ions by green algae species Chlamydomonas reinhardtii-a group of pollutants typically present in water whose purification is being attempted. These ions are essential for microbial growth but toxic if left unchecked to flow directly into the environment.
This mutualistic relationship between algae and yeast is more than simple enhancement of oxygen production and uptake of pollutants. According to Professor Yamada, these microbes pose no health risk to humans and have a beneficial impact on their ecosystems; hence, they are the perfect microbes for using environmental applications in treatment systems where treated wastewater is returned directly to natural systems. Apart from purification of the wastewater, this method may have further environmental and economic advantages. Both green algae and yeast accumulate valuable compounds inside the cells, such as polysaccharides, fats, and oils. The latter can be considered potentially tappable by-products of the process of cleaning wastewater, thus meaning that while cleaning water pollution, useful compounds are being simultaneously created. For example, they can be converted into microbial fertilizers that add value to the wastewater treatment process by providing a stable source of nutrients for agriculture.
This work represents an important step towards making wastewater treatment more sustainable, capable of eliminating external dependency on oxygen sources, cutting energy costs and producing beneficial by-products. It is in the alignment of their natural metabolic processes by yeast and green algae that researchers are envisioning innovations that prove to increase the efficacy of water treatment while working to protect the environment. This new discovery may soon make alga-yeast blend combinations move from laboratory application into mainstay usage in wastewater treatment facilities all over the world, in concert with the international call for energy-saving and eco-friendly technologies.