The meat and dairy industry across Europe is dependent on the production of grass. However, faced with competing pressures to reduce the environmental impact of agriculture, a potential future reduction of meat and dairy consumption in western diets, and pressure to minimize food production costs, grass could be used to produce alternative products. The biological production of polyhydroxyalkanoates (PHA) by using grass as the primary carbon source in a novel mixed culture process has been studied. A total of 30,000 t of fresh grass would yield approximately 403.65 t of dried biopolymer granules. On the basis of this early stage, non-optimized process, the cumulative energy demand (CED) of PHA produced from waste grass and cultivated grass was found to be 248.4 MJ/kg and 271.8 MJ/kg, respectively, which is the same order of magnitude as fossil-carbon-based polymers. Improvements in volatile fatty acid yields, reduction in chemical and water inputs, and using residues to make other products will reduce the CED. Given the future requirement to produce polymers with little or no fossil-carbon feedstock, an optimized version of the process could provide a viable future production option that also contributes to the long-term sustainability of agricultural communities.

中文翻译：

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通过绿色生物精炼利用草生物生产聚羟基链烷酸酯 (PHA)：材料和能量流

整个欧洲的肉类和乳制品行业都依赖于草的生产。然而，面对减少农业对环境影响的竞争压力、未来西方饮食中肉类和奶制品消费量的潜在减少以及将食品生产成本降至最低的压力，草可以用来生产替代产品。已经研究了在新的混合培养过程中使用草作为主要碳源的聚羟基链烷酸酯 (PHA) 的生物生产。总共 30,000 吨新鲜草将产生大约 403.65 吨干燥的生物聚合物颗粒。在此早期非优化过程的基础上，发现废草和栽培草产生的 PHA 的累积能量需求 (CED) 分别为 248.4 MJ/kg 和 271.8 MJ/kg，这与基于化石碳的聚合物处于同一数量级。挥发性脂肪酸产量的提高、化学品和水投入的减少以及使用残留物制造其他产品将降低 CED。鉴于未来需要使用很少或没有化石碳原料生产聚合物，该过程的优化版本可以提供可行的未来生产选择，这也有助于农业社区的长期可持续性。