来源：《新科学家》
原文见刊日期：2023年5月13日
Meat produced from cultured cells could be 25 times worse for the climate than regular beef unless scientists find ways to overhaul its energy-intensive production.
除非科学家们找到办法彻底改变人造肉能源密集型的生产方式，否则用培养细胞生产的肉对气候的危害可能是普通牛肉的25倍。
Lab-grown or “cultivated” meat is made by growing animal stem cells in a nutrient-rich broth. It has been proposed as a greener alternative to conventional meat because it uses less land, feed, water and antibiotics than animal farming and removes the need to farm and slaughter livestock, which are a major source of greenhouse gases.
实验室培育的肉是通过在营养丰富的肉汤中培养动物干细胞制成的。它被认为是传统肉类的绿色替代品，因为它比动物养殖使用更少的土地、饲料、水和抗生素，并且不需要饲养和屠宰牲畜，而牲畜是温室气体的主要来源。
However, Derrick Risner at the University of California, Davis, and his colleagues have found that the global warming potential of cultivated meat – carbon dioxide equivalents emitted for each kilo of meat produced – is 4 to 25 times higher than for regular beef.
然而，加州大学戴维斯分校的里斯纳和他的同事发现，人造肉的全球变暖潜能值——每生产一公斤肉排放的二氧化碳当量——比普通牛肉高4到25倍。
The researchers conducted a life-cycle assessment estimating the energy used in each step in the production of cultivated meat. They predict this will be similar regardless of which animal’s cells are used.
研究人员进行了一项生命周期评估，估计了人造肉类生产过程中每一步所消耗的能量。他们预测，无论使用哪种动物的细胞，结果都是相似的。
They say the nutrient broth has a large carbon footprint because it contains sugars, growth factors, salts, amino acids and vitamins that each come with energy costs. For example, energy is required to grow crops for sugars and to run labs that extract growth factors from cells. Each component must also be purified using energy-intensive techniques like ultrafiltration before they can be mixed into the broth.
他们说，营养肉汤的碳足迹很大，因为它含有糖、生长因子、盐、氨基酸和维生素，每一种成分的生产制造都需要消耗能量。例如，种植糖作物和运行从细胞中提取生长因子的实验室都需要能量。每种成分还必须使用超滤等能源密集型技术进行纯化，然后才能混合到肉汤中。
This “pharmaceutical-grade” purification ensures there are no contaminants like bacteria, says Risner. “Otherwise the animal cells won’t grow, because the bacteria will multiply much faster,” he says.
里斯纳说，这种“医药级”净化确保没有细菌等污染物。“否则动物细胞不会生长，因为细菌会繁殖得更快，”他说。
Pelle Sinke at CE Delft, a consulting company in the Netherlands, and his colleagues published a life-cycle assessment of cultivated meat in January that found its carbon footprint would be lower than that of beef.
荷兰CE-Delft咨询公司的佩尔·辛克和他的同事们在1月份发表了一份人造肉生命周期评估报告，发现人造肉的碳足迹将低于牛肉。
However, their analysis, part-funded by the Good Food Institute, a cultivated meat advocacy group in Washington DC, modelled a future in which pharmaceutical-grade components were replaced with less pure ones termed “food-grade”. “We assumed that it will be possible to make this transition from pharma-grade to food-grade in the future,” says Sinke.
然而，他们的分析(部分由华盛顿特区的一个人造肉倡导组织“好食品研究所”资助)模拟了一个未来，即药品级成分被不那么纯净的“食品级”成分所取代。辛克说：“我们认为将来有可能从制药级过渡到食品级。”
At the moment, all cultivated meat is grown in pharmaceutical-grade broths, but the Good Food Institute said that “cultivated meat companies are moving towards an input supply chain that is suitable for use in food production, rather than built for pharmaceuticals”. Risner isn’t sure this will be feasible because even trace levels of contamination can destroy animal cell cultures. Nevertheless, it may be possible to make animal cells more resilient, he says.
目前，所有的人造肉都是在制药级肉汤中生长的，但好食品研究所表示，“人造肉公司正朝着适合食品生产的原料供应链发展，而不是为制药而建”。里斯纳不确定这是否可行，因为即使是微量的污染也会破坏动物细胞培养。尽管如此，他说，使动物细胞更有适应性是可能的。
These issues need addressing before lab-grown meat production is scaled up, says Risner. “$2 billion has already been invested in this technology, but we don’t actually know if it’s going to be better for the environment,” he says.
里斯纳说，这些问题需要在实验室培育的肉类大规模生产之前得到解决。他说：“这项技术已经投入了20亿美元，但我们不知道它是否对环境更好。”