"The first steps towards microbial agronomy are being taken in an oasis in the desert."
Microalgae are invisible to the human eye, and yet under certain circumstances, they can achieve densities visible from space. In keeping, we often overlook their vast influence on our most valuable ecosystems. These microscopic plants contribute at least half of the world’s primary oxygen production. They sustain the marine food chain as we know it. And yet, their current influence is only a fraction of their inherent potential. Just as the domestication of terrestrial plants in the Neolithic period was a necessary precondition for feeding humanity as we know it today, domesticating microalgae may be the key to sustainably feeding our ever-growing population in the future. If we harness and concentrate their power, these tiny mainstays of the marine food chain may soon become a pillar of our diets.
The Power of Microalgal Blooms
Microalgal blooms occur in upwelling waters, when nutrient-rich, deep water rises to the upper illuminated layers of the ocean. Not coincidentally, this is the 1% of the ocean where more than half of the world’s commercial fishing occurs. The open ocean is a desert by comparison, making these spaces small oases, which happen to have the primary productivity of terrestrial rainforests. Microalgae bloom under very specific conditions, nesting the marine food web, and triggering atmospheric carbon capture. And their blooming is a far more transient phenomena than in terrestrial plants. Their organic matter turnover time (2-6 days) is three orders of magnitude faster than terrestrial plants (19 years). They produce half of the world’s primary oxygen using only 0.2 % of the plant global biomass. If only we could harvest those microscopic plants quickly enough before they sink forever into their depths!
An unlikely interaction of biology, physics, and chemistry produces this rare event in nature: the proliferation of a single, dominant, microbial species. In nature, most microbes (such as yeast, bacteria, fungi) bloom in a complex community, much in the same way wilderness areas are formed in a consortium of plant species. These naturally-occurring microalgal blooms should be regarded with the same awe as a cornfield spontaneously growing in the middle of the jungle. They pose a challenge: what if we could select a microalga with the right nutritional profile from the dizzying array in our oceans, and artificially mimic the “blooming” of a nutritional algae species?
A growing community of scientists and farmers has been working towards mastering and reproducing microalgal blooms in an agricultural setting. They are working on the assumption that this diverse and valuable resource can be domesticated like any other terrestrial crop. Microalgae domestication is a broad and evolving concept, which draws on many different technologies, some of which are common to the cultivation of other microbes in industrial microbiology, but ultimately are applied with the simplicity of a farming operation.
As Vice-President of R&D of the microalgae company iWi, I have focused my efforts on the Nannochloropsis species, because of its capacity to produce a nutritionally important omega-3 fatty acid that terrestrial plants are unable to make. This species produces eicosapentaenoic acid (EPA 20:5 n-3) attached to glycolipids and phospholipids, which is likely the most bioavailable form of omega-3. We have studied how, why, and under what conditions they express this product of interest, and we are continuously devising strategies to express as much of it as possible.
We selected this strain of Nannochloropsis for its capacity to thrive under our target environmental conditions, using techniques such as high throughput screening and directed evolution. While those initial approaches to finding better strains are common to industrial microbiology, our goal is to grow algae using a simpler and more sustainable farming approach. We reproduce a microalgal bloom using open ponds all year-round in a consistent and repeatable way, while amplifying the intensity of those blooms beyond what we typically observe in nature. This is a new type of agronomy: instead of growing fields full of wheat or corn, we are farming microbes.
This new concept of “microbial agronomy” operates at the intersection of agriculture and industrial microbiology. We seek to reproduce and enhance monoalgal blooms like those that spontaneously occur in nature by studying the biology of not just our target microalga, but also the microbiome associated with the algal bloom.
Producing commodity products from microbes may require a technology that can address microbial control in a manner different from what is common in industrial microbiology. Instead of physically separating our culture from contaminants using costly stainless steel fermenters and steam sterilization, our use of open ponds is an attempt to create an artificial microbiome that helps support the microalgal bloom. That means harnessing the natural capacity of microalgae and their hosts to thrive under exposed conditions. Growing microbes in open ponds is a farming practice rather than an industrial operation. In doing so, we are democratizing industrial microbiology into something that is closer to agriculture.
There are a wide range of techniques and biotechnological strategies that allow us to safely grow microalgae consistently throughout the year. We monitor our cultures, optimizing them for each season and geographical location. Fortunately, our algae like to grow in conditions that a lot of other microbes don’t like, which makes it a bit easier to protect from bad players. When necessary, we apply the same integrated pest control strategies one would apply to any other crop. We use techniques such as adjusting the pH or salinity of our cultures when needed, but we never use herbicides or pesticides.
Transforming the role algae play in our society
Microbial agronomy fills an economic niche that no other food production process can, and does so in a highly sustainable way. Algae can take resources once seen as waste and turn them into plant-based food such as omega-3 and protein. At iWi, rather than drawing omega-3 from caught fish and krill, we “skip the middle fish” and go straight to the original source of this nutrient. Algae grown in shallow open ponds in geographical locations that receive a lot of sunshine (such as our site in the Chihuahua desert in New Mexico) can achieve much higher cell densities than in nature.
This process utilizes arid land that can’t be used for other farming purposes, brackish water that eliminates our reliance on the planets already strained fresh water supply, and sunlight which is in ample supply on our farms. These are the first steps towards the domestication of microalgae in our lifetime. Just last year algae were included for the first time as a crop in the US Farm Bill. These steps are opening the door for new agricultural processes that will eventually transform the role microbes like microalgae play in our society.