A prototype conveyor belt system works to co-culture microalgae with a methanotroph. Its designers say aquaculture producers could use the system to manage their waste and create a potential revenue stream. Photo courtesy of BioSynsortia.
Could microalgae culture on a conveyor belt catch on?
Wednesday, January 13, 2021, 04:00 (GMT + 9)
Alabama-based BioSynsortia aims to make aquaculture and agriculture waste management a profitable endeavor
Microalgae, nutritional building blocks for fish and shellfish, are of growing importance to aquaculture feed manufacturers. Rich with long-chain omega-3 fatty acids, microalgae hold a small but growing share of the alternative-ingredient market.
While the major elements in microalgae production are provided by nature, mainly sunlight, a great deal of space is required to cultivate it. Microalgae is traditionally grown in shallow split ponds that are about nine or 12 inches deep. But the algal cells that are not at the very surface of the water don’t get much light. The ponds are, as a result, large and spread out, making collection costly, inefficient.
A new business formed by researchers at Auburn University in Alabama, USA, is taking aim at the expenses and the very dimensions of this process, first by allowing sunlight to do its job more effectively and without acres and acres of room.
The prototype Circulating Coculture Biofilm Photobioreactor. Photo courtesy of BioSynsortia.
Enter the Circulating Coculture Biofilm Photobioreactor, or CCBP. BioSynsortia CEO Matthew Hilliard told the Advocate to think of the CCBP as a pond-meets-conveyor belt system tailor-made for aquaculture producers like catfish or shrimp farmers who could feasibly use the system to upcycle their waste streams into a useful and nutritious food source. The coculture system comprises both a microalgae and a specific heterotrophic bacteria, a methanotroph that consumes methane, an abundant carbon source in aquaculture effluent.
“Nutrients to grow microalgae – nitrogen and phosphorous – can come at severe costs. Lab scale – even large scale – the cost can be high if it’s in a soluble salt form,” Hilliard said. “Biomass productivity in ponds is low. They need a lot of sunlight to grow. Even if you’re in the desert, with plenty of land and sun, the biggest challenge is then harvesting that biomass.”
Hilliard and his business partners – Dr. Peter He, president, and Dr. Jin Wang, chief technology officer – are colleagues at Auburn, which boasts one of the leading aquaculture programs in the United States, drawing students from all over the world. Auburn works extensively with the U.S. catfish industry, which could provide a business match for BioSynsortia.
Aquaculture pond discharge water is rich in ammonia and nitrites, and for it to be recycled back into culture water, biofilters are required. But by feeding the waste materials to the microalgae – along with another bacteria to consume the carbon dioxide and methane – it consumes the nitrogen and phosphorous in the liquid phase, allowing the microalgae to grow. It breaks down the waste, removing ammonia, and produces a harvestable and edible biomass.
“We envision that our technology will significantly reduce the need for split-pond systems and instead enable farmers to utilize the additional ponds for cultivating more aquaculture products,” said Hilliard.(continued...)
/ Global Aquaculture Advocate | Read the full article by clicking the link