Whether through open ponds, raceways or closed photobioreactors (PBR), growing algae is both a science and an art. Just as there are numerous ways to grow algae, its uses are exponentially varied: high-end nutraceuticals, cosmetics, pharma ingredients, fine chemicals, food ingredients, proteins for livestock and aquaculture, and biofuels. In the biofuels category alone, some companies focus on lipids to manufacture biodiesel and renewable diesel, others target sugars to ferment into ethanol, and still others concentrate on general biomass production to produce bio-oil or green crude.<\/p>\n
While open ponds may be right for some applications, Miguel Olaizola, director of production science with Heliae Development LLC, says PBRs have certain advantages over open systems. PBRs can, for example, offer some protection from contamination, but they can\u2019t eliminate it completely. \u201cThis means that the costs associated with taking down a culture, cleaning the system and reinoculating can be lower since the frequency of culture crashes is expectedly lower,\u201d Olaizola tells Biomass Magazine. \u201cPBRs can also be more efficient at utilizing the carbon dioxide provided to phototrophic cultures, again lowering costs.\u201d He says PBRs can also save on water usage since evaporation is better controlled, noting that in warmer locales this may lead to higher cooling costs. \u201cIn places where windblown sand and dust persist, PBRs can keep the ash content of the crop low,\u201d Olaizola adds. \u201cFinally, cultures in PBRs can be more effective at harvesting sunlight while minimizing photo-inhibition, resulting in a higher photosynthetic efficiency.\u201d<\/p>\n
The No. 1 reason closed PBRs may be better than open ponds for growing algae is light distribution, says Paul Woods, founder and CEO of Algenol LLC. \u201cGetting a little light to the maximum number of cells is the key, and there is ample evidence now that vertical beats horizontal by at least two to one,\u201d Woods says. \u201cIt\u2019s also important to be able to manage passively or actively factors such as temperature, pH, salinity, oxygen, nutrient levels and contaminants.\u201d Woods says the closed system allows for better passive, systematic and automated controls of the conditions necessary for optimum growth. \u201cOur system also allows the entire culture to have sun exposure and doesn\u2019t require expensive mixing,\u201d he says.<\/p>\n
Ultimately, closed PBRs may be better than ponds for certain products but not for others, according to Olaizola. \u201cAlso, they may be better for some parts of the process, such as seed or inoculum production, but not for others, like very large-scale units,\u201d he says, adding that in the end, one should judge a specific growth system on a very simple metric: money spent (capital expenses plus operating expenses) per ton of final product generated of a certain quality.<\/p>\n
Algae Systems
\nLast August, Algae Systems LLC announced successful completion of a unique algae demonstration unit with Japan\u2019s IHI Corp. located at a wastewater treatment plant in Daphne, Alabama. The PBRs take up about a half-acre of space but instead of using up precious land, they float in Mobile Bay. The setup is unique; not only is algae grown for biofuel conversion, but in doing so, Algae Systems provides a service to Daphne Utilities by treating 40,000 to 60,000 gallons of wastewater per day. \u201cWe\u2019re connected to their sewer line, so we take dirty water from them and give clean water back to them,\u201d says Eric Sundstrom, principal research engineer with Algae Systems. \u201cThe wastewater supplies all the nutrients the algae need, and a vast majority of the carbon.\u201d The continuous batch system is totally enclosed, so nothing is taken from or dumped into the bay. Gravity feeds the wastewater into the PBRs and once algae blossom through photosynthesis while consuming nutrients and carbon, the raw, aqueous algae is pumped into the plant where it is dewatered. The treated water is then discharged through regular, permitted channels.<\/p>\n
Algae Systems grows entirely natural, ecological polycultured strains. \u201cWe don\u2019t actively control what we grow,\u201d Sundstrom says. \u201cWhat happens is, different strains dominate at different times of the year due to environmental conditions and ecology predation. If one strain is taken out by a predator, many other strains are present to fill that need. It\u2019s a stable system, and we need that because we cannot have crop failure. If we do, wastewater treatment goes down. We don\u2019t have culture crash, just variation in the dominant strain.\u201d<\/p>\n
Mobile Bay is home to 24 of these floating bags. They are made of flexible plastic and are 150 feet long by 6 feet wide. They are durable too. Mobile Bay has alligators, and on occasion they like to get atop the PBRs and soak up the sun.<\/p>\n
The company is on its second-generation of PBRs. \u201cWe did a complete redesign,\u201d Sundstrom says. \u201cWe corrected everything we learned from the first generation.\u201d<\/p>\n
For starters, the whole system is automated via PLC controls, so it can be easily run without anyone attending it. Durability was also improved. \u201cWe streamlined it and eliminated failure points,\u201d Sundstrom says. Algae Systems works with famed shoe company Nike on the plastic material. \u201cIt\u2019s a better UV-stabilized material,\u201d he says. The second-gen units are also twice as big as their predecessors.<\/p>\n
\u201cWe try to keep costs low because you can\u2019t get much cheaper than two layers of plastic, flexible film,\u201d Sundstrom says, \u201cso we\u2019re trying to drive the cost of plastic down, for which we pay a small premium now.\u201d Another unique design component is the cooling and mixing effects of the water on which the PBRs float. \u201cWe can make use of any body of water for cultivation requiring no infrastructure and no leveled land,\u201d Sundstrom says. \u201cAlso, our design can run a system with no added carbon dioxide\u2014the wastewater provides ample organic carbon, it\u2019s a very nice gas exchange. The algae produce oxygen as they grow, and there\u2019s enough carbon in most wastewater to get full wastewater treatment in our system with no added carbon dioxide.\u201d He says while there are some benefits to adding carbon dioxide to the PBRs, it\u2019s not necessary.<\/p>\n
Algae Systems\u2019 conversion approach, in partnership with Auburn University, is a hydrothermal liquefaction process that utilizes wet algae, saving time and money on drying. Hydrothermal liquefaction can also extract oil from nonlipid portions of algae biomass. \u201cThat\u2019s important because we\u2019re not growing pure, high-lipid strains in our system,\u201d Sundstrom says. The end result is bio-oil suitable as-is for bunker fuel or further hydrotreating into renewable diesel or biojet fuel.<\/p>\n
Sundstrom says Algae Systems will continue refining its PBR system. \u201cAt this stage, it\u2019s no longer about proof of concept, but mechanical reliability, performance and scale-up,\u201d he tells Biomass Magazine.<\/p>\n
Algenol
\nAlgenol\u2019s Direct-to-Ethanol technology is a unique, two-step process that produces ethanol directly from the algae. Algenol then converts the spent algae biomass to biodiesel, green gasoline and biojet fuel. The company currently has two demonstration facilities, one in Ft. Myers, Florida, and another in India near Reliance Industries Ltd.\u2019s oil refinery, the largest in the world. \u201cWe have approximately 7,000 [PBR] units in Florida at our demonstration facility, and a smaller unit in India,\u201d says Woods. \u201cWe are currently planning for the same size unit in India as in Florida.\u201d<\/p>\n
Algenol\u2019s 100-liter PBRs are constructed of a flexible plastic film with a proprietary design that best facilitates ethanol production and biomass collection. \u201cThe plastic used for PBR construction has been specifically engineered and enhanced to optimize a variety of performance metrics,\u201d Woods says. \u201cEach individual PBR consists of ports for ethanol and biomass collection and the introduction of carbon dioxide.\u201d He says Algenol\u2019s PBRs are designed to maximize light exposure to all cells, to evenly dispense carbon dioxide throughout the culture, and to last many years in the field. \u201cOnce the PBRs are deployed, it\u2019s important for everything to be automated to save time and money,\u201d he says. \u201cNutrient and carbon dioxide levels are monitored and adjusted in an automated fashion to allow for the most optimal growth conditions. After a batch of algae is harvested, the bag is cleaned in place and reinoculated with the next batch.\u201d<\/p>\n
Annually, Algenol\u2019s PBRs produce 8,000 gallons of liquid fuels per acre. A majority of the liquid fuel is ethanol, with about 1,000 gallons of gasoline, jet, and diesel fuel refined from the green crude. \u201cThis compares favorably to corn at 420 gallons per acre per year,\u201d Woods says. \u201cWe use 5 percent of the land that corn ethanol uses to make the same amount of fuel, so our land use is much more efficient than other biofuels. In addition, we don\u2019t need farmland\u2014we need marginal land. We also use saltwater, not freshwater, in our process.\u201d<\/p>\n
Through the years, Algenol has experimented with several different plastics, orientations, sizes and spacing, and found that its current PBRs produce the best yields. \u201cWe\u2019ve evolved from horizontal to vertical design, from smaller sizes to larger sizes,\u201d Woods says. \u201cPerhaps most significantly, we now manufacture our own PBRs, which allows us greater control over the product.\u201d He says outdoor testing has proven Algenol PBRs are durable, lasting up to three years. \u201cWeather-ometer testing simulates eight years,\u201d Woods says. \u201cSo far, we target six years in the field.\u201d<\/p>\n
Woods says the state of PBR art today is varied, and often changed to best suit the product being produced and its value. \u201cWe will always continue to do R&D to further drive yield and reduce cap-ex,\u201d he says. \u201cWhile we are happy with our ability now to produce fuel for $1.30 a gallon and to produce 8,000 gallons per acre per year, we are always seeking to do even better. Future improvements will come from enhancement to our PBRs and to our algae strain itself.\u201d He adds that it\u2019s important to emphasize PBRs\u2019 ability to concentrate carbon dioxide uptake. \u201cOne metric ton of carbon dioxide fed into the Algenol process produces around 144 gallons of fuels,\u201d he notes, adding that algae technologies such as Algenol\u2019s are the only solution to mitigating climate change while monetizing carbon dioxide through utilization. \u201cThis drastically alters the current paradigm by turning an environmental and economic liability into a revenue-generating asset,\u201d he says.<\/p>\n
Heliae Development
\nHeliae Development manufactures a whole array of programmable PBRs of different sizes and capacities, depending on the purpose of a specific culture, Olaizola says. \u201cOur PBRs are designed to provide optimal growth conditions for specific crops,\u201d he says. \u201cThey\u2019re designed to adjust, in real time, growth conditions such as pH, nutrient concentrations, temperature and more.\u201d He explains that the effectiveness of control of growth parameters is, itself, dependent on a good understanding of turbulence within the reactor. \u201cDepending on the unit, the PBRs may have a photic zone, a zone for gas exchange, a zone for temperature control, shade control,\u201d he says. Different probes provide signals that are communicated to a PLC programmed to respond to those signals by adjusting, for example, valves that permit carbon dioxide to be bubbled into the culture or add nutrient components on demand. \u201cThis approach offers us the flexibility to use the same PBR for very different crops,\u201d he says.<\/p>\n
The smallest-scale PBRs Heliae uses are standard lab units\u2014flasks and carboys\u2014up to 20 liters. The next step in scaling up includes the use of proprietary plastic PBRs with capacities of up to 400 liters. \u201cDepending on the crop, we also use glass tubular reactors up to 550 liters,\u201d Olaizola says. The smaller units have two functions\u2014product development and production of inoculum, or seed, for larger production units. The larger units consist of open-channel reactors protected by a greenhouse-type structure that provides the benefits of closed PBRs at a very large scale. \u201cOur newest PBR has a capacity of 600,000 liters over a 4,000-square-meter footprint,\u201d Olaizola says. \u201cWe use some of the smaller units in mixotrophic mode\u2014the algae receive both sunlight and fixed carbon (e.g., acetate), which results in productivities of 1 to 1.5 grams per liter per day equivalent, in our system, to 1 to 1.5 kilograms per square meter per day.\u201d<\/p>\n
Olaizola says what makes Heliae\u2019s PBRs unique is harnessing not only phototrophic growth platforms, but also mixotrophic. \u201cThis is accomplished by combining the right vessel with the specific production mode,\u201d he says. \u201cWe have PBRs from lab-scale to 130,000-liter capacity that can be used in mixotrophic mode. The ability to shift a culture between purely phototrophic and mixotrophic production modes sets us apart. It gives us the ability to modulate the production of certain cellular components, which results in a more valuable crop.\u201d<\/p>\n
The company has two dozen PBRs of different designs and scale at its facilities in Gilbert, Arizona, along with one system at Arizona State University (also in Gilbert), and six systems in Japan. \u201cWe recently conducted a six-month demonstration test using some of our units colocated at an incinerator plant in the city of Saga in southwest Japan,\u201d Olaizola says. The project in Japan [with Sincere Corp.] has now moved into the construction phase of a commercial facility using our proprietary technology and reactors.\u201d Commissioning is expected early next year.<\/p>\n
Some of Heliae\u2019s reactors have been in operation for several years, but proper preventive maintenance has maintained the systems, which Olaizola says have run nearly continuously. \u201cPerhaps the most common repair needed every few months is a bad pH probe,\u201d he says. \u201cOn occasion, high winds have produced tears in our large PBR greenhouse covers.\u201d This happened twice in the past year.<\/p>\n
Two drivers guide Heliae\u2019s PBR development efforts: increasing the flexibility of each system for different products and species, and lowering the cost of the unit itself and its operation. \u201cIn general, we have developed PBRs that permit better control of parameters such as pH, temperature, gas exchange and turbulence,\u201d Olaizola says. The company is currently working on two aspects of PBR development, one of which is exploration of different construction materials that can lower the cost of larger units. \u201cSome of these materials will be cheaper to purchase\u2014think polymer versus glass tubes, for example\u2014and also cheaper to maintain,\u201d Olaizola says. This allows greater longevity and easier cleaning. \u201cSecond, we are pushing automation of functions so that manpower costs can also be reduced,\u201d Olaizola says. \u201cHeliae has always been big on automation. Now we are pushing that functionality even further.\u201d<\/p>\n
Heliae is in collaboration with several partners to continually improve not only its PBRs, but also other aspects of the production cycle. It\u2019s working with Evodos on downstream processing, specifically using its separation equipment. \u201cAnd more specifically, pertaining to the PBRs themselves, we\u2019ve been working with Schott, testing their new oval glass tubes in our Helix platform, a tubular PBR,\u201d Olaizola says.<\/p>\n
Schott also collaborates with Algatechnologies Ltd. The two signed an R&D agreement following a successful one-year study of new glass tubes at Algatechnologies\u2019 production facility in Israel. Schott\u2019s thin-walled Duran glass tubes significantly improved cultivation efficiency in the yields of Algatech\u2019s AstaPure natural astaxanthin, an antioxidant. The two firms partnered in 2013 to produce nearly 10 miles of thin-walled Duran glass tubes for testing in Algatech\u2019s PBR systems in Israel.<\/p>\n
In addition to Evodos and Schott, Heliae is also working with Philips Lighting for indoor and outdoor work, using newly developed LED units to decrease the heat load in indoor PBRs, and to augment natural sunlight in outdoor systems, Olaizola says. \u201cAnd considering that strain development is an intrinsic part of success in our field, we are working with Triton Health and Nutrition to scale up the indoor and outdoor cultivation of algae designed to produce high-value therapeutic proteins.\u201d<\/p>\n
Olaizola says the algae industry is \u201cfar from where we need to be\u201d regarding state of the art. He says algae can generate many products such as nutrition, energy and materials, along with services such as water reclamation, carbon capture and heavy metal remediation, but at a high cost. \u201cA large part of the current cost relates to the cost of the growth units themselves,\u201d he says. \u201cWe need to make those units a lot cheaper. Alternatively, we will limit ourselves to produce high-value products like astaxanthin or specialty proteins. But those markets are small.\u201d He says to manufacture algae-derived products at a more competitive price, the emphasis should not only be on PBR designs, but also the protocols developed to optimize their operation, including ancillary support systems from the inoculum to downstream processing platforms.<\/p>\n","protected":false},"excerpt":{"rendered":"
Whether through open ponds, raceways or closed photobioreactors (PBR), growing algae is both a science and an art. Just as there are numerous ways to grow algae, its uses are exponentially varied: high-end nutraceuticals, cosmetics, pharma ingredients, fine chemicals, food ingredients, proteins for livestock and aquaculture, and biofuels. In the biofuels category alone, some companies […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","nova_meta_subtitle":"","footnotes":""},"categories":[5572],"tags":[],"supplier":[10270,1325,541,2826,4752,4986,10412,10413,9823,10414],"class_list":["post-27622","post","type-post","status-publish","format-standard","hentry","category-bio-based","supplier-algae-systems-llc","supplier-algenol","supplier-arizona-state-university","supplier-auburn-university","supplier-evodos","supplier-heliae","supplier-ihi-corporation","supplier-philips-lighting","supplier-schott-north-america","supplier-triton-health-and-nutrition"],"_links":{"self":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/27622","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/comments?post=27622"}],"version-history":[{"count":0,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/27622\/revisions"}],"wp:attachment":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media?parent=27622"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/categories?post=27622"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/tags?post=27622"},{"taxonomy":"supplier","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/supplier?post=27622"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}