Bugs Produce Plastics from Waste

A process inwhich bugs eat industrial sludge and convert it to plastics is moving close tocommercial reality in Sweden.

AnoxKaldnesof Lund, Sweden, is commissioning two new facilities that are one step fromcommercial production of polyhydroxyalkanoate (PHA) plastics from industrialand municipal wastewater.

"Over thelast couple of years, we have operated a pilot-scale facility that hassuccessfully served to prove the concept of polyhydroxyalkanoate (PHA)production from wastewater treatment," says Simon Bengtsson, a researchscientist at AnoxKaldnes.

"Inparticular, we have confirmed that our PHA produced by open mixed culturestreating wastewater have similar or even superior material properties comparedto PHA produced from pure microbial cultures and refined substrates," addsBengtsson.

There are manycommercial ventures under way to produce PHA bioplastics using pure microbial cultures,a costly process. In fact, one of the biggest hurdles facing bioplastics istheir cost structure versus plastics made from petroleum and natural gas. ProjectedPHA prices from current commercial venturesare in the $2.25 to $2.75 per pound range. The competitive oil-based plasticsare priced below $1 per pound. The prices from the new wastewater process areexpected to be closer to oil-based plastics.

Commercialventures scaling up PHA production using fermentation processes include Telles,USA ; Biomer Biotechnology Co., Germany; PHB Industrial, Brazil; Mitsubishi GasChemical, Japan; Kaneka, Japan; Biomatera, Italy; Jiangsu Nantian Group, China;Tianan Biologic Material, China; and Lianyi Biotech, China.

PHA plasticsare biodegradable and could be used in packaging and even some moldedautomotive components that do not require high temperature tolerance.

In theAnoxKaldnes' approach, the feedstock is a biomass created from organic matterthat is removed from wastewater, such as what's left over from pulp and paperproduction.

The sludgeis enhanced with nutrients and oxygen, and then the bugs go to work. The basicidea is that bacteria and other organisms store PHA as a source of carbon andenergy for their survival.

Researchersat AnoxKaldnes have been able to boost PHA content to 42 percent of sludge by dryweight.

The workby the company has been partly supported by the European Union Neptune project,which also includes as a partner the Advanced Water Management Centre at TheUniversity of Queensland, Australia.

Productionof bioplastics is expected to grow at a compound annual growth rate above 40percent through 2015, according to a new report from BCCResearch.

A Californiacompany called Micromidasis also exploring the potential to produce bioplastics from wastewater.