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Bioreactors and Microalgae · Hydroponics Daily

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Hello, welcome back to Hydroponics Daily, your go-to podcast for everything soilless cultivation.
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I'm your host Dr Russell Sharp and not only is it soilless cultivation today,
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it's even grown media-less because we are talking bioreactors and growing microalgae.
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So this is an interesting subject.
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Microalgae are not technically plants but they photosynthesize and
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so they will come under botany at the
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very least and you grow them
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in greenhouses and grow rooms so i'm going
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to talk about them because they'll be very similar and i've got
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a tiny bit of experience when it comes to
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this because we've sold some fertilizers
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to some microalgae startup companies in the past some
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raw materials so we'll talk about that so microalgae
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are tiny photosynthetic powerhouses they're key for biofuels wastewater
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treatment nutritional supplements and even
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hydroponic system integrations so we'll talk about that what
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is a bioreactor so a bioreactor is a
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system that's designed to support living organisms and they're
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sort of they culture any microbe
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they might come in an open system or a closed system so
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an open system these are called often called raceway ponds
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and you will see them they're often popular in like africa
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in polytunnels and the microalgae
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go around the tanks and it looks a
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bit like a formula one racetrack or certainly an indie racetrack a bit simpler
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than a formula one one and then you have closed photobioreactors pbrs these
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are sealed systems with precise environmental controls they're a bit like the
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systems that are used for growing microbes in like microbiology for like.
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Antibiotic production and they have like glass but they have a glass outer system and they have like.
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Propellers to move the solution around and
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so it's a sealed system and there might
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be long tubes in bigger systems and the
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key is to move the algae around rather than leave them stagnant that's
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not just to make sure that they get gas exchange and nutrient
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mix up and don't clump together it's it's
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said that the light can penetrate and there's a whole host
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of different reasons reasons why you want want to do that so
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microalgae absorb co2 they use water
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and light to grow rapidly and high density
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systems can produce really high biomass if optimized
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and that's the key some speeds can reach
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growth rates that far exceed terrestrial crop
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plants so but you obviously need to manage
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the light distribution the co2 that's dissolved in
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or bubbled through the water and mixed the temperature ph nutrient levels need
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to be optimized and it has to be sterilized as well to prevent the growth of
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organisms that you don't want in there Other types of algae and other bacteria and farges,
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viruses that affect bacteria and microalgae. What's going to be in there?
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Any organism that's going to eat the microalgae, like protozoa,
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amoeba, you want to make sure they're not in there.
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So it gets really complicated very quickly and you have to be a specialist in
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microalgae cultivation.
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Algenuity, I think that's a company based in like, say, Albans or Bedfordshire in the UK.
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They they're experts in this and they do things
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like they extract pigments from microalgae
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for use high value pigments some of the pigments from microalgae
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costs can reach really high figures like hundreds of thousands of dollars for
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a kilo of the pigments from microalgae omega fatty acids you can extract from
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microalgae rather than having to use animal products or without having to use GM crops,
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that's a big source of omega fatty acids now.
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Gm canola or oilseed rape
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so i said we have the raceway ponds the
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tubular bioreactors flat plate or
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bubble columns where they so the column goes up into
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the air and you bubble co2 and air through
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it which helps with agitation as well and foil-based or biopolymer react sheet
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reactors they're flexible low-cost options all depends on the scale and the
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application you know for biomass and biofuels oil rich algae is obviously what
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you're after there for biodiesel production and extraction where up to 60% of the biomass can be oil.
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Obviously you're going to need to have a massive energy efficient system for
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that. It's not going to be LED powered is it because you're sunlight powered.
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Wastewater treatment. Some bioreactors can be used to clean up wastewater,
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remove nitrates and things like this and can be integrated into hydroponic systems.
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I've not seen that done in real life.
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And then you've got advanced biotech systems that use genetically
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engineered algae to produce vaccines enzymes
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and even anti-cancer agents and then
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if you think about it some facilities can link algae bioreactors
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to flue gases out of factories to reduce greenhouse gas emissions and that's
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really the golden ticket isn't it imagine having a a energy intensive system
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like imagine a cement factory that produces colossal amounts of co2 or a steel refiner a steel.
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What do they call them furnace that would produce vast amounts of co2 and so
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could you link that to a biomass producing or even a high value producing microalgae production,
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because you know you've got super high growth rates massive
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co2 capture minimal land use low waste
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and so yeah potentially massive so what
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are the challenges light limitation algae is
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self-shading and reduces photosynthesis at high cell densities so i said that
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movement of the algae is critical oxygen buildup and closed systems can inhibit
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the growth ironic isn't it the oxygen levels in the in the solution can build
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up i guess like eventually it could lead to a um an issue where the gases could
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be, you could have a fire risk.
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Contamination, that would be the biggest issue for me. In open ponds,
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reducing the purity, consistency.
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If you're using all that pumping, if you're using synthetic CO2 rather than
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flue gas and temperature control, there can be lots of energy.
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And then how do you harvest it? There's going to be massive issues around biomass
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separation. Could you use membranes and mechanical separation?
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These have all been studied in great detail there are books and books and books
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on this subject and this is just a quick,
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podcast episode so don't expect to know everything about
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microalgae production but maybe to whet your appetite obviously
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hydroponics is key is is there's a big link up
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between hydroponic feeds and microalgae feeds and the
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nutrients that are required very similar nutrients are required for microalgae
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you might find that there is a sodium requirement some
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of the microalgae might come from seawater and they might
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need some sodium in there so you could provide that with sodium nitrate
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or sodium chloride so salt
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or you could provide it as any other
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sodium salt that you you want
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to provide there are lots of different options if you want
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to and they're a lot cheaper than potassium salts so you
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can produce a investigation solution you can just add sodium nitrate
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to gold leaf or liquid gold and away you go you won't need
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to bother with a and b tanks and make it a lot simpler and obviously
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it'd have to be it's going to be more akin to sort of deep water culture so
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you might need to use things like sterilization systems to clean out the system
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every now and again some of the systems can be fairly large as i said some of
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the raceways sort of biomass levels you're looking at it's like 10 grams per liter of solution.
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And they can capture 60 to 95 percent nitrogen and phosphorus that's put into
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them daily which is massive you wouldn't get that from a plant and then the
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algae rich effluent can be used to enhance zucchini seedling growth so you could
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use it as a biostimulant there is a lot of research in.
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Spain i believe about microalgae use as
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sort of like um freshwater algae as an alternative to seaweed biostimulants
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one of my former bosses rye wagner of agrinus he said he was the head of a company
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or certainly yeah i think he's the ceo of a company in spain that looked at,
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algae as a biostimulant. I don't know if they're still going.
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They probably are. So it's a consistent, sodium-free, low environmental impact,
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potentially, biostimulant.
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Chlorella is a human stimulant additive you'll find in growth shops, I think.
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Spirulina as well, that seems to ring a bell. I'm not sure if that's grown.
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Bioreactors think it probably is.
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Yeah, there's certainly lots to consider there. They're not just futuristic tech,
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although they will feature in a lot of films you
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know a lot of sci-fi films will contain
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will you'll see bioreactors because they'll just look flipping
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brilliant i mean compared to a hydroponic system hydroponic systems look
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good and you know are impressive but bioreactors
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look 10 times that if you want to look
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at bioreactors then a good place to
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go i don't know they still got them but there is a greenhouse in cambridge
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university botanical gardens that contains bioreactors
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and you can look at it from outside if
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you're a visitor to the gardens i'm not
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sure if they're running that you might be the day that you go there everything's down
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and the project's not running but if you're going to find a bioreactor that's
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the place to go maybe email them and say just before you
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go to cambridge then you could go
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and look at the bioreactors there and if
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you asked them and said you'd like to have a tour of the facilities i'm sure they
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would be more than happy to give you a tour if you're sensible and
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positive and you know not an idiot because they
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get money from the government to help with
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plant science and spread you know and they get and help
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with industrial application of science
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and things like this cambridge university botanical gardens is my favorite botanical
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gardens in the uk and that is saying something because there are some fantastic
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botanical gardens in the uk q gardens obviously and wisley the rhs gardens edinburgh.
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Botanical Gardens is great.
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Ness Botanical Gardens in Liverpool holds a special place in my heart.
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But I would say, because that's what got me into plant science in the first
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place, Durham Botanical Gardens, because that used to be on my doorstep as a student.
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But Cambridge is brilliant. I like it because everything is logically set out in plant families.
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A lot of them, they have weaving paths
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that take you on a journey and all garden design and
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things like this principles i don't want cambridge university none
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of that no garden design principles everything plant families is a block there's
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a block of bedding plots and all the species of that family are in that bed
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and then the next one is the next family the next one is the next family and
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you just go brilliant just go around and it's really easy to find and and there's an amazing teak.
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Wooden greenhouse there and in the
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middle of winter that's a great place to go and i
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think it's just a fantastic place cambridge itself is a wonderful
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city and you've got the bioreactors as well it's got
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a fantastic cafe with really good food and coffee and i
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used to take a load of students there when i was a lecturer and i
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would say to them right we can either take the park and
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ride and lose two hours a day or we could illegally park the
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double yellow lines outside the Botanical Gardens and if
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we get a parking ticket we all agree to share the price the
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cost of that parking ticket which will be less than the park and ride and all
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the students would say yeah let's do that so we would park outside and we never
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once got a parking ticket but we I did have to drive off very quickly when I
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saw a parking warden coming around the corner and she was just about to write
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me a ticket so yeah definitely recommend Cambridge Botanical Gardens and their,
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exhibits which may or may not include my croggy when you go there so as I say
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I am not an expert there are lots of different types of microalgae and lots
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of experts on microalgae and there's lots of different types like pigmented
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microalgae purple microalgae.
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And if you you'll obviously need a microscope
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to study the different types and there's diatoms as
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well so that are like they have a silica body
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around them so you'll need silicon nutrition if you're going
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to grow certain types of microalgae you'll need the sodium if
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you're going to see what the types but yeah that's been
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hydroponics daily for today a sort of gentle introduction to bioreactors
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and microalgae maybe you're doing this already and
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you think i've missed something got something wrong or just massively
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glazed over the whole subject and there's loads more to it than what
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i've talked about and i'm more than happy for you to send
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me the details and i'll do a follow-up episode about bioreactors but
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that's been hydroponics daily for today if you know somebody's into microalgae
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send me this episode and ask them what they think of it that would be great
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and if you've had this episode shared with you then you owe the person who shared
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it with you a very cold nice drink so get down to the pub or the bar or wherever
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you're located or buy them an
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ice cream that's been hydroponics daily for today until tomorrow goodbye.