Cheese whey (CW) is the main by-product of the dairy industry and is often considered one of the main agro-industrial biowaste streams to handle, especially within the European Union, where the diary activities play an essential role in the agrarian economy. In the paper, Life Cycle Assessment (LCA) is used to analyse the feasibility of producing polyhydroxyalkanoates (PHA) as the main output of an innovative CW valorisation route which is benchmarked against a conventional anaerobic digestion (AD) process. To this aim, the LCA inventory data are derived from lab-scale PHA accumulation tests performed on real CW, while data from the literature of concern are used for modelling both the PHA extraction from the accumulating biomass and for the alternative CW valorisation through AD. The comparison shows that AD would have better environmental performances than the baseline PHA production scenario. For example, the climate change indicator values result 44.8 and −35.7 kg CO₂ eq./t CW for the baseline PHA recovery and AD, respectively. LCA proved to be a useful tool to highlight the weak points of innovative processes and suggest proper improvements. Once improved and again analysed through the LCA, the PHA production process from CW shows that environmental performance comparable to AD may be achieved. With reference, again, to the climate change indicator the value can be reduced to −50.3 kg CO₂ eq./t CW for the improved PHA production process.

奶酪乳清 (CW) 是乳制品行业的主要副产品，通常被认为是需要处理的主要农业工业生物废物流之一，尤其是在欧盟内，乳制品活动在农业经济中发挥着重要作用。在本文中，生命周期评估 (LCA) 用于分析生产聚羟基链烷酸酯 (PHA) 作为创新 CW 增值路线的主要输出的可行性，该路线以传统厌氧消化 (AD) 工艺为基准。为此，LCA 清单数据来自对实际 CW 进行的实验室规模 PHA 积累测试，而来自相关文献的数据用于对从积累的生物质中提取 PHA 和通过 AD 进行替代 CW 估值进行建模。比较表明，AD 将比基线 PHA 生产方案具有更好的环境性能。例如，气候变化指标值导致 44.8 和 -35.7 kg CO₂ eq./t CW 分别用于基线 PHA 回收率和 AD。LCA 被证明是一种有用的工具，可以突出创新流程的弱点并提出适当的改进建议。CW 的 PHA 生产过程经过改进并再次通过 LCA 进行分析后，表明可以实现与 AD 相当的环境性能。再次参考气候变化指标，对于改进的 PHA 生产过程，该值可以降低到 -50.3 kg CO ₂ eq./t CW。