How engineered microbes could help feed the world’s crops
How engineered microbes could help feed the world’s crops
工程微生物如何助力全球粮食生产
EXECUTIVE SUMMARY Fertilizer is crucial for the global food supply, but making it uses a lot of energy and produces a lot of emissions. Some companies hope microbes can help. A growing body of research shows that seeding the soil around a crop’s roots with beneficial microbes can help feed the plant, providing crucial nitrogen to help it grow. This could help reduce the need for chemical fertilizer, production of which accounts for roughly 2% of global greenhouse-gas emissions. It could also cut costs for farmers, a big boon—especially as the Iran war has sent energy and fertilizer prices skyrocketing in recent months.
执行摘要 肥料对于全球粮食供应至关重要，但其生产过程不仅消耗大量能源，还会产生大量排放。一些公司寄希望于微生物能提供帮助。越来越多的研究表明，在作物根部周围的土壤中播撒有益微生物，可以帮助植物获取生长所需的关键氮元素。这有助于减少对化学肥料的需求，而化肥生产约占全球温室气体排放量的 2%。此外，这还能降低农民的成本，这在近期因伊朗战争导致能源和化肥价格飙升的背景下，无疑是一大福音。
Humans have used biological fertilizers like manure for thousands of years, and companies have long been developing microbial fertilizers, including some that rely on genetic engineering. But it’s difficult to engineer microbes that can reliably provide nitrogen for crops while also thriving themselves. A startup called Switch Bioworks is taking a new approach that essentially allows microbes to establish themselves and grow into healthy colonies before shifting into nitrogen-producing mode. “We have to reinvent fertilizer,” says Tim Schnabel, the company’s founder and CEO.
人类使用粪肥等生物肥料已有数千年历史，而各公司长期以来也一直在开发微生物肥料，其中一些依赖于基因工程技术。然而，要设计出既能可靠地为作物提供氮元素，又能自身茁壮成长的微生物并非易事。一家名为 Switch Bioworks 的初创公司采取了一种新方法：让微生物先在土壤中定殖并长成健康的菌落，然后再切换到固氮模式。“我们必须重塑肥料，”该公司创始人兼首席执行官 Tim Schnabel 表示。
The air is nearly 80% nitrogen, but plants can’t use that “free” nitrogen directly because it doesn’t react readily with other elements. Instead, they rely on so-called fixed nitrogen, which has been converted into more reactive compounds such as ammonia. In nature, microbes can perform this nitrogen fixation. Some plants, like legumes, even have symbiotic relationships with nitrogen-fixing bacteria, housing them in nodules in their roots. Synthetic fertilizer is essentially industrial nitrogen fixation via the Haber-Bosch process, which uses natural gas to make ammonia that’s applied to fields.
空气中近 80% 是氮气，但植物无法直接利用这种“免费”的氮，因为它不易与其他元素发生反应。相反，植物依赖所谓的“固定氮”，即转化为氨等更具反应性的化合物。在自然界中，微生物可以进行这种固氮作用。一些植物（如豆科植物）甚至与固氮细菌建立了共生关系，将它们寄生在根部的根瘤中。合成肥料本质上是通过哈伯-博施法（Haber-Bosch process）进行的工业固氮，该工艺利用天然气制造氨，然后施用到农田中。
Biological fertilizers aim to replace some of the synthetic fertilizer with microbes that can help fix nitrogen for plants. But one challenge microbial fertilizer companies have run into is that it’s energetically expensive for microbes to make and release ammonia. Putting all their energy into nitrogen fixation can hamper their growth. There’s a certain level of colonization you want to see around the roots, Schnabel explains. It’s too expensive and logistically challenging to put all those microbes on the plant, so you have to rely on a smaller number of microbes to grow and divide, establishing the population.
生物肥料旨在用能够帮助植物固氮的微生物来替代部分合成肥料。但微生物肥料公司面临的一个挑战是，微生物制造和释放氨的能量成本很高。将所有能量投入固氮作用会阻碍它们自身的生长。Schnabel 解释说，你希望在根部周围看到一定程度的定殖。将所有这些微生物直接施加到植物上既昂贵又在后勤上难以实现，因此必须依靠少量的微生物进行生长和分裂，从而建立起种群。
Switch Bioworks is betting that a genetic switch is the answer. A genetic switch is a section or sections of DNA that controls how genes are turned on and off. In this case it works by activating genes that help trigger ammonia production in and release from the cell. The company is working on several options for setting off this change in its microbes. The leading one is to have the microbes react to the nitrogen level in the soil: Once it drops to a certain level, they begin producing ammonia.
Switch Bioworks 押注于“基因开关”这一解决方案。基因开关是一段或多段控制基因开启和关闭的 DNA。在这种情况下，它的作用是激活那些有助于触发细胞内氨产生和释放的基因。该公司正在研究几种触发微生物发生这种变化的方案。最主要的一种是让微生物对土壤中的氮含量做出反应：一旦氮含量降至一定水平，它们就开始产生氨。
“You have this inherent biological reality, where it’s really expensive for microbes to fix nitrogen,” says Dan Blaustein-Rejto, director of food and agriculture at the Breakthrough Institute. It takes a lot of energy, and if they do fix the nitrogen, they want to use it for themselves, to build proteins and survive, he says. Adding genetic switches could help microbes grow and thrive and then help fertilize crops.
“存在一个内在的生物学现实，即微生物固氮的代价非常高昂，”突破研究所（Breakthrough Institute）食品与农业主任 Dan Blaustein-Rejto 说。他指出，这需要消耗大量能量，如果微生物确实固定了氮，它们会倾向于将其留给自己，用于构建蛋白质和生存。添加基因开关可以帮助微生物在生长壮大后再去帮助作物施肥。
Switch is currently trialing its product in six US states, though it’s two to three years from a commercial product, Schnabel says. It’s initially focused on corn, the most-planted crop in the US, with over 90 million acres in 2026. “It’s too early to tell exactly how well this works in the field,” Schnabel says. The company plans to harvest the plants in late October or early November, but as of August, some corn plants treated with Switch microbes already looked visibly healthier than those that hadn’t. And it’s still developing the products that will eventually make it to the market, he says.
Schnabel 表示，Switch 目前正在美国六个州对其产品进行试验，距离商业化产品还有两到三年的时间。公司最初专注于玉米，这是美国种植面积最大的作物，2026 年种植面积超过 9000 万英亩。“现在判断它在田间的实际效果还为时过早，”Schnabel 说。公司计划在 10 月底或 11 月初收获作物，但截至 8 月，一些使用 Switch 微生物处理过的玉米植株看起来已经明显比未处理的更健康。他说，公司仍在开发最终将推向市场的产品。
Switch’s products could significantly help to clean up agriculture. “There’s a lot of potential for these companies and products to help farmers reduce emissions,” Blaustein-Rejto says. “This could be a really important solution for a quite hard-to-abate sector.” While lab results have been promising, field trials are a crucial step in proving a product, Blaustein-Rejto says: “This is one of the final steps before they can go to market and make strong claims to farmers.” Independent trials are important as well, he adds, since there can be a large gap between a company’s reported data and what independent researchers find.
Switch 的产品有望显著助力农业减排。“这些公司和产品在帮助农民减少排放方面潜力巨大，”Blaustein-Rejto 说。“对于一个减排难度极大的行业来说，这可能是一个非常重要的解决方案。”虽然实验室结果令人鼓舞，但田间试验是验证产品的关键步骤，Blaustein-Rejto 补充道：“这是产品上市并向农民做出有力承诺前的最后步骤之一。”他还指出，独立试验同样重要，因为公司报告的数据与独立研究人员的发现之间可能存在巨大差距。
Pivot Bio is another company working to bring microbes to fields. Since it was founded in 2011, its products have been used on millions of acres of crops. The company now produces a range of products: Some versions can be added when seeds are planted, while others are applied to seeds before they’re even on a farm. The company also recently expanded beyond corn to make microbial fertilizers for cotton, wheat, and small grains including sorghum and barley.
Pivot Bio 是另一家致力于将微生物引入农田的公司。自 2011 年成立以来，其产品已应用于数百万英亩的农作物。该公司目前生产一系列产品：有些版本可以在播种时添加，而另一些则在种子进入农场之前就已施用。该公司最近还将业务扩展到玉米以外，开始为棉花、小麦以及高粱和大麦等小粒谷物生产微生物肥料。
Pivot’s initial challenge was trying to get microbes to produce nitrogen, whether they sensed it in the soil or not. Now the company is working to figure out how to make fitter, more robust colonies no matter the environment, says Travis Frey, the company’s chief technology officer. “Growers right now are experiencing a double whammy from the farm economics point of view,” he says. Fertilizer costs are going up, and the price of commodity crops like corn has dropped. That’s a big opportunity for Pivot and others in the industry, Frey says: “This next decade is when biologicals on the farm are going to go mainstream.”
Pivot 的最初挑战是试图让微生物产生氮，无论它们是否感知到土壤中存在氮。该公司首席技术官 Travis Frey 表示，现在公司正致力于研究如何让微生物菌落在任何环境下都能更健康、更强壮。“从农业经济的角度来看，种植者目前正遭受双重打击，”他说。化肥成本在上涨，而玉米等大宗农作物的价格却在下跌。这对 Pivot 和行业内的其他公司来说是一个巨大的机会，Frey 说：“未来十年，农用生物制品将成为主流。”
Fertilizer and seeds are two of the biggest costs for many growers, so reducing dependence on synthetic fertilizers could be a major help for agriculture, says John Havlin, a professor in the department of crop and soil science.
作物与土壤科学系教授 John Havlin 表示，肥料和种子是许多种植者最大的两项成本，因此减少对合成肥料的依赖将对农业产生重大帮助。