Algae Biopolymers

Biopolymers or organic plastics are a form of plastics derived from renewable biomass sources such as vegetable oil, corn starch, pea starch unlike fossil-fuel plastics derived from petroleum. Biopolymers provide the twin advantages of conservation of fossil resources and reduction in CO₂ emissions, which make them an important innovation of sustainable development.

Algae serve as an excellent feedstock for plastic production owing to its many advantages such as high yield and the ability to grow in a range of environments. Algae biopolymers mainly evolved as a byproduct of algae biofuel production, where companies were exploring alternative sources of revenues along with those from biofuels. In addition, the use of algae opens up the possibility of utilizing carbon, neutralizing greenhouse gas emissions from factories or power plants.

Algae based plastics have been a recent trend in the era of bioplastics compared to traditional methods of utilizing feedstocks of corn and potatoes as plastics. While algae-based plastics are in their infancy, once they are into commercialization they are likely to find applications in a wide range of industries.

Types of Algal Bioplastics

Bioplastics are plastics manufactured using biopolymers derived from two routes:

• Biopolymers from living organism � these are typically made from cellulose, soy protein and starch.
• Polymerizable Molecules � these are typically made from lactic acid and triglycerides, wherein these molecules come from renewable natural resources, and can be polymerized to be used in the manufacture of biodegradable plastics.         

 Source: http://www.biobasics.gc.ca/english/View.asp?x=790#top 

The various plastics that can be made from algae feedstock include:

1. Hybrid Plastics

�   These plastics are made by adding denatured algae biomass to petroleum based plastics like polyurethane and polyethylene as fillers. It thus decreases the amount of petroleum used per unit of plastic, and often provides these plastics with very desirable properties including biodegradability.

�   Filamentous green algae of the order Cladophorales are claimed to be well suited for use in hybrids.

2. Cellulose-based Plastics

�    The oldest forms of Bioplastics, first made over a century ago, are a cheap and low quality family of plastics that are derived from cellulose, a naturally occurring biopolymer of glucose.

�    For some strains of algae, 30% of the biomass produced after extraction of algal oil is known to contain cellulose. These strains are thus ideally suited to be feedstocks for cellulose-based bioplastics.

3. Poly-Lactic Acid (PLA)

�   Lactic acid is usually produced by fermentation of feedstocks and it is polymerized to produce polylactic acid.

�    Lactic acid and its polymer poly-lactic acid (PLA) are already used as a biodegradable alternative and are believed to be economically viable alternatives on a large scale in the future.

�     Lactic acid can be produced by bacterial fermentation of algal biomass.

4. Bio-Polyethylene

�    The monomer used in the production of polyethylene is ethylene, which is easily produced from ethanol, by a chemical reaction called cracking.

�    The ethanol is presently derived from natural gas or petroleum; however it can also be derived from bacterial digestion of algal biomass, or directly from algae.

�   However, it is not economically feasible since algae derived ethanol is much costlier than petroleum derived ethanol.

While the above types of plastics from algae are technically feasible, their economic (cost) feasibility is still being worked out.

Algae Strains that are used in manufacturing Biopolymers

Nostoc sp, Phormidium mucicola , Chlorella stigmaaphora, Chlorella vulgaris, Chlorella pyrenoidosa, Chlamydomonas mexicana, Ulva lactuca, Scenedesmus obliquus, Scenedesmus braziliensis, Stichiciccis bacillaris, Anabaena flos-aquae, Porphyridium aerugineum, Porhyridium cruentum.

Growth Conditions of Algal species used in manufacturing Biopolymers

Cultivation of algae requires a nutrient medium containing nitrogen and other nutrients, illumination with light energy, optimal temperature, pH and salinity.

 Production Process

Various processes for the cultivation of algae and production of biopolymers exist. Fundamentally, two stages exist: first stage, in which algae growth is initiated and a second stage where the biopolymer is carried to completion. U.S Patent No. 4079544 describes a biopolymer synthesis procedure employing a culture medium with traces of sodium nitrate and sodium glycerophosphate. In the first stage, the algae culture is subjected to continuous artificial illumination. In the second stage, the illumination is terminated and the culture is subjected to diurnal cycles of solar radiation and darkness. In addition to this, carbon dioxide an air is introduced into the culture by which biopolymer production is carried out.

Applications of Algal Biopolymers

The advantages of biopolymers over traditional plastics are unprecedented, provided that they are used in situations in which they raise the functionality and generate extra benefits. As mentioned above: biopolymer is a sustainable material and it can be produced from renewable resources. The practical side of the use of biopolymers is the economical advantage for industries and municipal works. These consist of the saving of raw materials and the reduction in costs when the products are finally discarded. Renewable biologically degradable products also plead for a sustainable economy. This means that the agricultural sector obtains the possibility to produce a rising percentage of its turnover extra as non-food products. After the disposal of the products can the recuperated materials been taken back by the agriculture as certificate quality-compost and the economical (and ecological) advantages are only a pleasant accidental.

• Thickening agents for mobility control in waterflood oil recovery
• Food additives
• Flocculants useful in waste water treatment
• Soil conditioning
• Drilling mud extenders
• Pet food
• Farm feed stabilizers
• Culture media from specialty crops like orchids
• Brewery fining
• Slurry stabilizer for pigments in ceramics & textile applications
• Biopolymers can be converted into packaging materials, which have the advantage of being renewable

Market and Commercialization status

Approximately a dozen of inherently biodegradable plastics are now in the market, with range of properties suitable for various consumer products. The global market for biodegradable polymers has reached 1.5 billion tons in the year 2000. In response to increasing public concern over environmental hazard caused by plastic, many countries are conducting various solid waste management programmes including plastic waste reduction by development of biodegradable plastic material. There is an intense research for making the biodegradable plastic. Some biodegradable plastic materials under development are: 1. PHA.s (Polyhydroxyalkonates), 2. Polylactides, 3. Aliphatic polyesters, 4. Polysaccharides, 5. Co-polymers and/or blends of above.

Prominent Players in the Biopolymers Market

1. Petro Sun is on the verge of utilizing its algae oil produced in the farm to bioplastics  research. Their primary objective of exploring bioplastics is to complement algae biofuel  production.

2. Dow Chemicals announced its partnership with Algenol Biofuels to build a pilot plant, which will use algae to convert carbon dioxide emissions into ethanol. Ethanol obtained would be used as one of the ingredients for Dow plastics. Dow plastics are quite interested in producing ethanol because they believe ethanol can replace fossil fuels in the production of ethylene, a feedstock for many plastics.

Source: http://www.treehugger.com/files/2009/07/dow-chemical-partners-algenolbiofuels-pilot-biorefinery.php 

3. Cereplast has been recently in the news for its compostable bioplastics made from food starches including corn, tapioca, wheat, and potatoes. The company believes that algaebased resins represent the latest advancement in bioplastics technology. Cereplast hybrid plastic is made by binding algae materials with oil-based polyolefins. The company has plans of producing 100% algae based bioplastic in future.

Source: http://www.designnews.com/article/457262-Algae_Biomass_Could_be_Central_to_New_Plastics_Compounds.php

4. Soley Biotechnology Institute produces bioplastic from Spirulina dregs. The company utilizes this dreg which is left as byproduct when extracting useful products from Spirulina.

Source: http://www.soley.cn/bioplastic.html

Challenges in Biopolymer Production

There are some issues concerning cultivation, harvesting and treatments leading to some uncertainty for the breakthrough of this promising way. Alginic acid and alginate polymer derivatives are well-known as hydroswelling, gelling and thickening additives but they also have uses as material for dental impression and moulding for soft or delicate objects or, in combination with other polymers, for specific applications.

The true innovative breakthrough can come from algae-based plastic grades, the ethanol and other alcohol routes leading to biopolyethylene, bio-PVC or bio-EVA.

Research Efforts in Biopolymers

There is an intense research for making biodegradable plastic. Some biodegradable plastic materials under development are: 1. PHA.s (Polyhydroxyalkonates), 2. Polylactides, 3. Aliphatic polyesters, 4.

Patents on Algae based Biopolymers

1.Algae biopolymer production 

Ramus; Joseph S. US Patent No: 4,236,349

http://goo.gl/AgFrs

The patent describes process and apparatus for the production of algae biopolymer employing a first stage for the growth of algae and a second stage for biopolymer production. In the first stage, growth of algae biomass in a culture medium is accomplished by operating the first stage in a continuous mode in which fresh nitrogen-containing nutrient medium is supplied to the culture. Concomitantly with the supply of fresh nutrient medium to the culture in the first stage, a portion of the culture medium is transferred from the first stage to the second stage in which the supply of nitrogen is limited. A nitrogen deficiency is created in the second stage to shift the culture to a senescent phase to enhance biopolymer production. The growth phase is carried out in a first stage reaction chamber which is connected to a plurality of second stage reaction chambers in parallel with one another. Culture withdrawn from the first stage is transferred sequentially to each of the second stage reaction chambers such that biopolymer production occurs in several second stage chambers simultaneously with cells produced in the first stage reaction chamber.

2.Process and culture composition for growth of alga and synthesis of biopolymer

Savins, Joseph George and Paul, James M. US Patent No: 4078331

http://www.freepatentsonline.com/4078331.html

 This specification discloses a process and a culture composition for growth of an alga and synthesis of biopolymer by the alga. The process involves growth of the alga and concomitant synthesis of the biopolymer in an aqueous culture containing as a source of phosphate for said alga dibasic sodium or dibasic potassium phosphate. The nitrogen source can be sodium nitrate or urea. Control of the pH of the culture is affected by injecting a mixture of carbon dioxide and air into the culture during growth of the alga and synthesis of the biopolymer. The carbon dioxide also serves as a source of carbon for growth of the alga and synthesis of the biopolymer and provides agitation/mixing within the culture chamber. Preferably, the mixture of carbon dioxide and air is injected continuously into the culture during the entire growth period of the alga.

3.Method for cultivating algae and a covering material used therefore

Harasawa, Isamu; Hariki, Yukio; Maeda, Katsuhiko; Nakamura, Kouichi. US Patent No: 4235043

http://www.freepatentsonline.com/4235043.html

A method for cultivating an alga, which comprises growing the alga in a light field substantially free from light of wavelengths of not more than 340 nm; and a covering material for use in the cultivation of algae, said covering material substantially inhibiting the transmission of light of wavelengths of not more than 340 nm.

 4.  Algae-blended compositions for thermoplastic articles

Shi, Bo; Wang, James H. US Patent No: 20100272940

http://www.freepatentsonline.com/y2010/0272940.html

A thermoplastic material composition containing certain biodegradable and renewable components is described. The thermoplastic composition that includes a least one kind of algae or a blend of at least one kind of algae and a plant polymer a blend of algae and/or plant-based polymers, such as proteins and starches, as relatively low cost feedstock. The algae or blend may be plasticized. Additionally, a method adapted for large scale fabrication of fibers, films, or extruded articles is also described.