AIM
- To investigate the sustainability of mixed culture polyhydroxyalkanoate (PHA) biopolymer production from wastewater through life cycle assessment (LCA) tools.
- Gain a greater understanding of the effects variability in both carbon source and nutrient addition has on the enrichment of PHA producing mixed cultures.
- Compare and contrast different wastewaters in the PHA production process and determine suitable wastewater characteristics for optimal PHA production.
SIGNIFICANCE
PHAs have the potential to replace many of the common petrochemical based polymers since they have similar physical capabilities but with the added benefit to be readily biodegradable. Typically, PHAs have been produced with pure cultures (often genetically engineered) using highly processed feedstocks such as corn glucose. This has made PHA production marginally economically attractive at best and, according to most studies, more environmentally harmful than the petrochemical polymers it replaces.
The benefits of mixed culture production of PHAs are twofold: much simpler production process and utilisation of cheap, unprocessed feedstocks, including wastewaters. Although mixed culture production is generally less productive than pure culture production, the large scale operation in the form of wastewater treatment processes mean that this process could generate a large amount of product which might enable the transition from petrochemical polymers to renewable "green" PHA polymers.
SKILLS AND APPROACHES
This work combines a number of tools from different fields to reach its objectives. LCA environmental management approach was used to justify further development of this green polymer. The intense process accounting in LCA has also highlighted a number of bottlenecks in the PHA production process, which in turn formed the experimental research questions of this project. The integration of biotechnology with analytical chemistry and statistical modelling has the potential to significantly change process control strategies applied in mixed culture PHA production.
OUTCOMES
- LCA has confirmed that the mixed culture process potentially a smaller environmental impact than petrochemical polymer production, and is an economically sustainable production process that is superior biogas production as value adding process from wastewater.
- PHA production in mixed cultures from a range of different wastewaters has been demonstrated with levels of accumulation consistently over 50% of cell dry weight.
- The aerobic feast/famine enrichment technique has been found to be stable and robust when using a range of wastewaters and operating parameters.
FUNDING
Australian Research Council Discovery Project DP0452860
PERSONNEL
- A/Prof Paul Lant – Project Manager and Advisor
- Prof Jürg Keller – Project Advisor
- Dr Alan Werker – Project Advisor and industry partner from AnoxKaldnes Biopolymer, Lund, Sweden
- Nicholas Gurieff – PhD Student
- Monica Arcos – Masters Student from UNAM, Mexico