| 1. |
- Dakers, A, et al.
(författare)
-
Ecosystem Services
- 2002
-
Ingår i: Understanding and Solving Environmental Problems in the 21st Century. ; , s. 127-138
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 2. |
- Heimersson, Sara, 1984, et al.
(författare)
-
Methodological issues in life cycle assessment of mixed-culture polyhydroxyalkanoate production utilising waste as feedstock
- 2014
-
Ingår i: New Biotechnology. - : Elsevier BV. - 1876-4347 .- 1871-6784. ; 31:4, s. 383-393
-
Tidskriftsartikel (refereegranskat)abstract
- Assessing the environmental performance of emerging technologies using life cycle assessment (LCA) can be challenging due to a lack of data in relation to technologies, application areas or other life cycle considerations, or a lack of LCA methodology that address the specific concerns. Nevertheless, LCA can be a valuable tool in the environmental optimisation in the technology development phase. One emerging technology is the mixed-culture production of polyhydroxyalkanoates (PHAs). PHA production by pure microbial cultures has been developed and assessed in several LCAs during the previous decade. Recent developments within mixed-culture PHA production call for environmental assessment to guide in technology development. Mixed-culture PHA production can use the organic content in wastewater as a feedstock; the production may then be integrated with wastewater treatment (WWT) processes. This means that mixed-culture PHA is produced as a by-product from services in the WWT.This article explores different methodological challenges for LCA of mixed-culture PHA production using organic material in wastewater as feedstock.LCAs of both pure- and mixed-culture PHA production were reviewed. Challenges, similarities and differences when assessing PHA production by mixed- or pure-cultures were identified and the resulting implications for methodological choices in LCA were evaluated and illustrated, using a case study with mixed- and pure-culture PHA model production systems, based on literature data.Environmental impacts of processes producing multiple products or services need to be allocated between the different products or services. Such situations occur both in feedstock production and when the studied system is providing multiple functions. The selection of allocation method is shown to determine the LCA results. The type of data used, for electricity in the energy system, is shown to be important for the results, which indicates, a strong regional dependency of results for systems with electricity use as an environmental hot spot. The importance of assessing water use, an environmental impact not assessed by any of the reviewed studies, is highlighted. © 2013 Elsevier B.V.
|
|
| 3. |
- Pisco, Ana R., et al.
(författare)
-
Community Structure Evolution and Enrichment of Glycogen-Accumulating Organisms Producing Polyhydroxyalkanoates from Fermented Molasses
- 2009
-
Ingår i: Applied and Environmental Microbiology. - 0099-2240. ; 75:14, s. 4676-4686
-
Tidskriftsartikel (refereegranskat)abstract
- An open mixed culture was enriched with glycogen-accumulating organisms (GAOs) by using a sequencing batch reactor and treating an agroindustrial waste (sugar cane molasses) under cyclic anaerobic-aerobic conditions. Over a 1-year operating period, the culture exhibited a very stable GAO phenotype with an average polyhydroxyalkanoate (PHA) content of 17% total suspended solids. However, the GAO microbial community evolved over the course of operation to a culture exhibiting unusual characteristics in producing PHAs comprised of short-chain-length monomers, namely, 3-hydroxybutyrate, 3-hydroxy-2- methylbutyrate, 3-hydroxyvalerate, and 3-hydroxy-2- methylvalerate, and also, up to 31 mol% of the medium-chain-length (MCL) monomer 3-hydroxyhexanoate (3HHx). Microbial community analysis by fluorescence in situ hybridization revealed a concurrent long-term drift in the GAO community balance, from mainly "Candidatus Competibacter phosphatis" to mainly Defluviicoccus vanus-related organisms. The production of 3HHx was confirmed by C-13 nuclear magnetic resonance (NMR) and appeared to be related to the increased presence of D. vanus-related GAOs. These results suggest a broadened spectrum of material, chemical, and mechanical properties that can be achieved for biopolymers produced by open mixed cultures from fermented waste. The increased spectrum of polymer properties brings a wider scope of potential applications.
|
|
