By Jan H. Schut
May be yes. May be no. They’re already grown on an industrial scale to make anti-aging pharmaceuticals and nutrients. But can algae also clean up industrial waste water and polluted fish farms? Convert CO2 emissions from utility and ethanol plants into oxygen? Make bioplastics? And replace fossil fuels? Those are tall orders for pond scum, but the emerging algae industry is targeting all of them—sometimes two or three at once.
BioProcess Algae LLC in Portsmouth, R.I. (www.bioprocessalgae.com), for example, just started up its first full size commercial algae plant on five acres next to Green Plains Renewable Energy Inc.’s bio ethanol plant in Shendandoah, Iowa (www.gpreinc.com). The algae farm eats CO2 emissions from the ethanol plant and produces animal nutrients. Algae carcasses after the nutrients are removed can potentially be used in bioplastics. BioProcess’ chief technology officer Toby Ahrens says they have been contacted by several research groups asking to sample algae residues for plastics.
The Algae Biomass Organization in Denver (www.algaebiomass.org), a four-year-old trade group formed to promote industrial algae, says the rapidly growing industry is already $1.2 billion/year. But that’s actually the value in 2010 of pharmaceutical algae (carotenoids) alone. (Pharmaceutical powders with 5-10% active carotenoids can also cost $300 to $3000/kg, according to a recent paper by Herminia Rodrigues, professor of biochemistry at the University of Seville in Spain.) All the other industrial applications for algae–waste water cleanup, CO2 emission abatement, bio fuel and bioplastics–are in stages of R&D or early commercialization.
Algae are single- or multi-celled organisms that can grow in water either alone or in strings or colonies. They can be macro like seaweed or micro like slime. They can be photosynthetic getting energy from sunlight, breathing in CO2 and respiring oxygen, then at night reverse and breath in oxygen and out CO2. Algae can also be heterotrophic, getting energy from sugars and continually respiring CO2. Brown algae, like Phaeophyceae, are usually marine and are used to remove heavy metals from water. Green algae are usually in fresh water, like macro algae found in fish farms, or microalgae Chlorella and Spirulina, which are used to purify waste water and remove CO2. The ritzy carotenoid-producing algae used by the pharmaceutical industry can be yellow and bright orange. Cyanobacteria are photosynthetic bacteria, not algae, also being developed to produce biomonomers and abate CO2.
Algae use in bioplastics is in its infancy. Three companies have published or announced blending algae into thermoplastics. Cereplast Inc., a compounder of starch-based biopolymers in El Segundo, Calif. (www.cereplast.com) compounds post-industrial algae into thermoplastics. Algix LLC in Bogart, Ga. (www.algixllc.com), a spinoff in 2010 from the University of Georgia in Athens (www.uga.edu), is developing blends of unprocessed algae into thermoplastics under a global license (U.S. Pat. Applic. # 20100272940) from Kimberly-Clark Corp. (www.kimberly-clark.com) in Irving, Texas (see this blog posted Nov. 8, 2011).
CEREPLAST COMMERCIALIZES WORLD’S FIRST ALGAE PLASTIC
In September 2009 Cereplast announced that it had successfully blended algae into PP. Cereplast had just licensed patented technology for making bio-content degradable polymers (U.S. Pat. # 7608649) from the University of Arkasas in Fayetteville (www.uark.edu) and wanted to offer algae-content in degradable polymers. But Cereplast assumed that post-industrial algae wouldn’t be available in large enough quantities until algae biofuels became commercial. Instead Cereplast found postindustrial algae were already available.
Different kinds of algae have different starch, fat, protein and fiber content, but post-industrial algae, which consists of the carcasses or cell walls left over after oil or medicinal contents have been extracted, is largely lignin and cellulose and fairly consistent regardless of algae type. “We care more about the industrial process the algae comes from than about the kind of algae,” says Cereplast senior v.p. of R&D Kelvin Okamoto.
Cereplast first developed algae-content thermoplastic in 2010 and introduced it commercially this year as Biopropylene 109D with 20% post-industrial algae biomass in PP. Biopropylene 109D is designed for thin-walled injection molding with density of 0.94 g/cc, melt flow index of 24 g/10 min. at 190 C and flex modulus of 125 kpsi (see data sheet). The first commercial application is for luxury hair accessories injection molded in France for the Barrette Factory in Hollywood, Calif. (www.dominiqueduval.com), which promotes Cereplast’s algae plastic on its website. Algae add some desirable properties, especially soft haptics, a natural feel, and better grip for hair products, says Jane Gauthier, designer for the Barrette Factory.
|Properties of Cereplast’s New Biopropylene 109D|
|Algae content, %||20|
|Tens. Strength @ max., psi||3,460|
|Tens. Elong. @ break, %||3.3|
|Tens. Modulus, kpsi||240|
|Flex. Modulus, kpsi||125|
|Flex. Strength, psi||3,630|
|Gardner Impact, in-lbf||20|
|MFI 190 C @ 2.16 kg||24 g/10 min|
|MFI 230 C @ 2.16 kg||78 g/10 min|
In packaging algae they can add biodegradability. Cereplast has experimental grades with up to 50% algae content. Algae also add color, either green or brown, and unfortunately odor. Both depend on the type of algae and the industrial process it comes from, so Cereplast keeps algae from different post-industrial sources separate. “Algae smell like the ocean,” notes BioProcess’ Ahrens, “but they shouldn’t smell like the ocean at low tide.” Processing algae to remove nutrients or oil reduces the odor, but when a closed box of plastic pellets with algae content is opened, it still smells. Secondary processing, however, for example by injection molding, reduces the odor further, so that Barrette Factory’s Gauthier says odor isn’t an issue.
ALGIX IS SCALING UP BLENDS OF ALGAE WITH PP AND PBAT
Algix this year received a $100,000 grant from the University of Georgia and $500,000 of private capital to scale up production of algae-content bioplastics. Algix initially took dried algae cultivated from waste water cleanup from Ven Consulting LLC in Melbourne, Fla., and ground it with a hammer mill to a particle size of around 250 microns. The algae was then compounded into polypropylene at up to 50% loading and extruded into sheet at Interfacial Solutions LLC, a contract R&D company in River Falls, Wis. (www.interfacialsolutions.com). Algix’s director of R&D Ryan Hunt notes that about 500 microns was the thinnest sheet they could make. Hunt had been in communication with Dordan Manufacturing Co. in Woodstock, Ill. (www.dordan.com), which wanted to test the new algae/PP sheet, so Algix sent Dordan the test roll. Dordan formed it and showed algae/PP test samples at Pack Expo in Chicago in October.
Algix next tried jet milling the dried algae to finer particle size (10 microns) and compounded it into both PP and poly(butylene adipate-co-terephthalate). In January 2013 Algix plans to make a larger run of 2000 lb of dried algae, compounded into both PP and PBAT to sample to companies that want to develop applications with it. One potential application is for injection molded containers for lawn and garden products, Algix’s Hunt says, where odor won’t be an issue. For injection molding the particle size of the algae doesn’t have to be quite as small as for thin films for packaging, Hunt adds.
ALGAE CAN ALSO MAKE BIO-POLYMERS
Growing algae to make jet fuel and gasoline, the application the government likes to talk about the most, is probably the farthest from commercialization, though there are over 30 start-up companies in the U.S. alone working on it. The criticism leveled at algae biofuel technologies is that they consume way too much fresh water and energy for aeration to be environmentally sustainable. The advent of inexpensive shale gas in North America is also likely to slow algae biofuels. But some algae biofuel companies target making chemical intermediates like bio ethanol and lactic acid for biopolymers.
Algenol Biofuels Inc. in Bonita Springs, Fla. (www.algenolbiofuels.com), has selectively enhanced cyanobacteria (U.S. Pat. Applic. # 20100297736 and 20120142066), which live in salt water, eat CO2 from industrial waste, and give off ethanol and fresh water without killing the bacteria. This saves time and resources needed to grow new bacteria and the cost of separating ethanol. Algenol is building a farm of closed plastic reactor tubes in Lee County, Fla., hoping to produce ethanol for around $1/gallon. “We also would consider converting ethanol into ethylene,” says Algenol’s chairman and CEO Paul Woods.
Inventure Chemical Inc. in Tacoma, Wash. and Tuscaloosa, Ala. (www.inventurechem.com), uses a catalytic reaction and esterification technology (U.S. Pat. Applic. # 20110162951) to convert algae to chemical intermediates like ethanol and also recovers starch and cellulose.
A new research group in Germany from the Institute for Synthetic Microbiology (www.synmikro.com), set up in 2010, with Philipps University in Marburg (www.uni-marburg.de) and Westfaelische Universitaet Muenster (www.uni-muenster.de), has come up with the first algal production of poly-3-hydroxybutyrate (PHB). Researchers injected the diatom Phaeodactylum tricornutum with three bacterial enzymes that together make PHB. After seven days, the algae accumulated granules of PHB up to 10.6% dry weight. That’s less far efficient than bacteria, which can yield 80wt% PHB, but with photosynthesis algae could be less expensive to grow.
Interesting high value polysaccharide polymers are also being extracted directly from specialized algae. Georgia Institute of Technology in Atlanta (www.gatech.edu) and Clemson University in Clemson, S.C. (www.clemson.edu) discovered a polysaccharide from brown marine algae that could allow greater energy storage in lithium ion batteries. The materials are being developed by Sila Nanotechnologies Inc. (www.silanano.com), a spinoff from Georgia Tech. Marine Polymer Technologies Inc. in Danvers, Mass. (www.marinepolymer.com) extracts chitin from brown algae, then extracts N-acetylglucoseamine monosaccharides from the chitin. It’s used to make dressings that can stop bleeding even from open wounds.