Everything you ever wanted to know about algae-based bioplastics and MORE!

January 23, 2012

WOW! As per my last post I was hoping my friend from Algix would get back to me with a more technical discussion of the company’s technology synthesizing bio plastics from algae and BOY HOWDY did I! Check out the awesome responses below.

QUESTION:

Please describe the relationship between textile manufacturers/dairy producers and algae. In other words, how does algae become a waste product of these industries’ process and how is it ideal for manipulation into bio-based plastics?

ANSWER:

Many types of algae and aquatic plants have been used for cleaning waters rich in inorganic nutrients, such as nitrogen and phosphorus compounds. The high nutrient content accelerates the growth rates and increases the protein content of a variety of “nuisance” algae and aquatic plants or “aquatic macrophytes”. The enormous “algal blooms” are seen as not only a nuisance but an environmental hazard due to the oxygen demand the algal cells require during night time respiration which can suffocate fish and other animals if the excess nutrients run off or leach into nearby water bodies. Many industries produce large amounts of nitrogen and phosphorus-rich waste-water, such as the agricultural livestock farms, i.e. dairies and swineries, fisheries, etc; as well as industrial sources such as processing plants for textiles, municipalities, distilleries, biorefineries, etc.

ALGIX, LLC is located in Georgia, hence we are focusing our efforts on industries in the southeast where we have longer growing seasons, a warmer climate and an abundance of water compared to north or southwest. The “Carpet Capital of the World” is located in Dalton, Georgia, which has over 150 carpet plants which produce millions of gallons of nutrient rich waste water. Research conducted at the University of Georgia, has demonstrated high growth rates from various strains of algae and isolated top performing microalgae strains for further development. ALGIX is in discussions with companies there to scale up biomass production and use cultivated algae as a bio-additive in their polymer containing flooring products. Likewise, we are also talking to a variety of compounders that can co-process and blend the aquatic biomass with other base resins, such as PE, PP EVA, PLA, PHA, etc. As product development progresses, various end use applications for algae-blended thermoplastics and bioplastics will arise, which will increase the demand for the raw aquatic feedstocks. The advantage is that industries can effectively capture their lowest-value waste product, i.e. nitrates and phosphates, through bioremediation using algae and aquatic macrophytes. Photosynthesis captures solar energy and converts the waste water nutrients into biomass which can then be used as a raw material for composite formulations to make resins and bioplastics.

As the demand for algal biomass increases, there will be an incentive for other industrial plants to build out algae based water treatment systems and sell the biomass. Livestock operations such as Dairies, Fisheries, etc located in the southeast and southwest can use algae to treat their manure effluents and provide additional biomass to the market. We are in discussions with large dairies companies for building out algal ponds for water treatment and biomass recovery. Over time the aquatic biomass will become a commodity product traded like other traditional agricultural crops. Currently, large amounts of corn are being diverted from food production and enter biofuel or bioplastic production. Thereby, introducing a new, low-Eco footprint biofeedstock will help alleviate the demand on food based crops for plastics and liquid fuel conversion.

QUESTION:

How is post-industrial algae synthesized into bio-based plastics? In other words, how is the protein in algae bound to the plastic components to allow for application to injection molding? What additives are required to allow for the synthesis OR used to increase the properties of the material? I remember discussions of protein-based materials (cellulous) vs. carbon-based (bio-PET) and how the former “connects” to the plastic molecule similar to how the calcium carbonate connects to the PP polymer, for example.

ANSWER:

Algae produced from wastewater treatment has been grown under nitrogen rich conditions, providing an abundance of nitrogen to make protein. During exponential growth phases in algae and aquatic plants, the composition of the biomass is dominated by protein, in the range of 30-60% depending on species. The higher protein content algae or post processed meals may have 50% or more protein which is similar to soy protein meal. Although some companies have announced efforts to refine the algal oils or ferment into ethanol, these approaches require additional refining for synthesizing into “bio-based” monomers and polymers identical to their petroleum counterpart, such as Bio-PET, or bio-polyethylene, etc.

The protein in the biomass is what our process uses as the “polymeric” material in the blends. Proteins, by definition, are polymer chains of amino acids, which offer a variety of hydrophobic and hydrophillic interactions based upon the amino acid profile. Through thermomechanical processing, such as twin screw extrusion, the heat and shear forces exerted on the native protein complexes force them to denature and unfold providing a network of elongated polymer-like threads when blended with a base resin. The proteins have hydroxl groups available that can hydrogen bond and covalently bond in the presence of polar side groups on polymer chains as well as maleated chemical interactions. By adding conventional coupling agents, tensile strength and moisture absorption can be significantly improved.

The remaining portion of the non-protein biomass is usually composed of carbohydrates such as cellulose, hemicellulose, polysaccharides, but have little to no lignin. The crude fiber portion of the biomass has been shown to act like a reinforcing agent, increasing stiffness and tensile strength, but reduces elongation. The Ash fractions can range from 10-30% depending on cultivation method, however we believe the ash or minerals, will behave like a mineral filler, similar to calcium carbonate as it will be homogeneously blended throughout the matrix along with the biomass. Algae grown for bioremediation generally have a low lipid content, around 10% or less, and in cases where algae is being grown for biofuels, with high oil contents, the oil will be extracted leaving a protein-rich post extracted meal which will be well suited for compounding. Other value added compounds, such as high value pigments and antioxidants may also be extracted which will help in being able to modify the plastic color from dark green or brown to a lighter color which is easier to mask with color additives. Biomass particle size is also an important variable and needs to be optimized depending on conversion technology and application.

We have been successful compounding algae blends with some base resins up to 70% bio, however the majority of our formulations used in injection molding are set at a 50/50 blend which provides stronger performance characteristics. However, pure 100% algae dogbones have been made under compression molding, but do not have the performance properties compared to the injection molded blends.

QUESTION:

What is the preferred end-of-life treatment of this unique bio-based plastic? Is it similar to the approach taken by PLA supplier NatureWorks, which looks to generate the quantity necessary to sustain the creation of a new closed-loop recycling process in which PLA would be recycled in its own post-consumer stream?

ANSWER:

In the case that Algae is compounded with biodegradable base resins such as PLA, PHA, PHB, TPS, PBAT, and others, the final bioplastic will have the same or higher degree of biodegradability. Since we are dealing with biomass, the algae component is consumable by microbes, and the slight hydrophillic nature of the resin allows water to penetrate and accelerate the biodegradation process under the proper composting conditions. ALGIX still is testing the biodegradability rate and cannot not comment on degradation curves yet, as most of our research has been on formulation, co-processing, and performance related milestones.

When biomass from any source is compounded with a base resin, the resulting formulation becomes distinct from the recyclable pure resin. This is even the case with different polymer composites that may have two or more resin constituents. Although the biomass will be able to sustain some level of recycling, due to the more fragile nature of the resins bio building blocks, the performance will likely decrease, as with most other conventional recycled resins. We do not necessarily see a unique algal-blended stream of plastics, just due to the numerous variables in the formulations. A recent study by the American Chemical Council found that the US has a dismally low recycling rate below 10% but the state of New Hampshire has an exceptionally high recovery rate of over 40%. Instead of recycling these materials, which requires sophisticated sorting equipment or lots of manual labor, an easier approach was to convert the non-recyclable plastic waste steam into energy using boilers for steam and electricity production. I believe they still recycled some of the more easily sorted materials, like plastic water/soda bottles, just used any non-spec plastic for waste-2-energy…This not only reduced the cost associated with handling and processing the numerous recycling streams, it provided a substantial amount of alternative energy. If algae blended with synthetic non-biodegradable polymers increases in usage, the biomass fraction essentially acts as a bioenergy source at the end of its lifecycle. The conclusion that the ACC drew was that there is a dramatic shift in the amount of states shifting their focusing from complex sorting/recycling to a more direct and streamlined waste-to-energy approach. As Waste-2-energy increases, the concern about having closed loop recycling, although a wonderful concept, will be alleviated because the “other” non-recyclable plastics now can be converted to energy instead of being landfilled. The algae fraction of the plastics represents a carbon neutral component of the resin and energy feedstock.

ALGIX is initially focusing on product streams of plastic that have a low or absent recycling rate due to various factors; these include paint cans, pesticides, fertilizers, mulch films, and carpet products. There exists active programs for recycling carpets by shaving the fibers and grinding the backings for use in new carpets (at some minor percentage) as well as pure post-consumer-grade base resins, usually PP based. New product lines can be generated using post consumer grade resins with post-industrial grade algae biomass to provide a bioresin with a very low eco-footprint. We have a research proposal pending on conducting an LCA based on the algae biorefinery approach for bioplastics to further quantify these environmental and economic benefits.

That should be enough for yall to chew on for a bit…

Let’s all give a big digital THANK YOU to Algix for being so informative and transparent with their exciting new technology!

One Response to “Everything you ever wanted to know about algae-based bioplastics and MORE!”

  1. […] at Pack Expo in Chicago, at McCormick Place, October 28th-31st. I strongly encourage you to visit this blog post, which describes the technology of synthesizing “algae plastics” from aquatic biomass, a waste […]

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