RESUMEN
Separate household food waste collection for anaerobic digestion is one method used in the sustainable management of biodegradable municipal solid waste (MSW). Recycling of food waste contributes to the UK's reuse, recycling and composting targets and can help local authorities boost plateauing rates whilst encouraging landfill diversion. This study explored the reasons for differences in the provision of food waste collections, using two comparable local authorities, one with a collection in Wales (Cardiff), and the other absent of such service in England (Southampton). A PESTLE analysis investigated the political, economic, social, technological, legal and environmental impacts of separate food waste collections. The greenhouse gas impacts of the collection and treatment systems of MSW in both cities were estimated for 2012/13. Results showed significant policy and legislative differences between devolved governments, that separate food waste collections can save local authorities significant sums of money and substantially reduce greenhouse gas impacts. A survey of one hundred respondents in each city aimed to understand attitudes and behaviours towards recycling, food waste segregation, cooking and purchasing habits. The number of frequent recyclers and levels of satisfaction were higher in the authority which provided a separate food waste collection. In the area which lacked a separate collection service, over three-quarters of respondents would participate in such a scheme if it were available.
Asunto(s)
Residuos de Alimentos , Residuos Sólidos/estadística & datos numéricos , Administración de Residuos/métodos , Inglaterra , Composición Familiar , Vivienda/estadística & datos numéricos , Eliminación de Residuos/métodos , Residuos Sólidos/análisis , GalesRESUMEN
The proteins present in gas vesicles of the cyanobacteria Anabaena flos-aquae and Microcystis sp. were separated by SDS-polyacrylamide gel electrophoresis. Each contained a protein of Mr 22K whose N-terminal amino acid sequences showed homology with that of the Calothrix sp. PCC 7601 gvpC gene product. The gvpC gene from A. flos-aquae was cloned and sequenced. The derived amino acid sequence for the gene product indicated a protein, GVPc, of 193 residues and Mr 21985 containing five highly conserved 33 amino acid repeats. The sequence was identical at the N-terminus to that of the Mr 22K protein present in gas vesicles and showed correspondence to seven tryptic peptides isolated from gas vesicles. This establishes that GVPc forms a second protein component of the gas vesicle, in addition to the main constituent, the 70 residue GVPa. Quantitative amino acid analysis of entire gas vesicles reveals that GVPc accounts for only 2.9% of the protein molecules and 8.2% of the mass present: this is insufficient to form the conical end caps of the gas vesicles. It is suggested that GVPc provides the hydrophilic outer surface of the gas vesicle wall; the 33 amino acid repeats may interact with the periodic structure provided by GVPa.