Using precision fermentation to optimize biofertilizer preparation

土壤施肥是农业的关键因素，氮是作物生产力最具限制性的养分。作为蛋白质、DNA和叶绿素的重要组成部分，氮对植物的健康生长发育至关重要。目前，世界上有一半的人口依靠Haber-Bosch工艺生产合成氮肥（SNF）。然而，所有化石燃料生产的1%被用于生产SNF。二氧化碳的成本是巨大的，但与肥料的二阶效应相比就相形见绌了，后者的效率只有30-50%。其余的以硝酸盐污染的形式进入水道，或以一氧化二氮的形式释放到空气中，造成巨大的环境破坏和人类健康问题。netzeronnitrogen （NZN）旨在通过为农民提供一种高效、天然、廉价的合成肥料替代品，消除合成氮肥每年造成的约11亿吨二氧化碳当量的温室效应。我们专注于一种特别有趣的植物生长促进内生重氮营养细菌，具有巨大的农艺潜力，我们的创新是建立一个具有特征菌株生物多样性的平台，以开发针对特定作物和环境条件的高度优化的接种配方。评估PGP的全范围活性（横跨一个文库的30个菌株）在世界上任何地方从未对这种细菌进行过评估。该项目资助了一种原型生物肥料产品的开发，该产品将导致NZN细菌在作物内部组织中强大，可靠和高水平的定植。利用诺丁汉大学世界一流的精密发酵设施，将利用NZN科学家开发的专有定植试验确定六种精英菌株的细菌细胞预处理优化。适应性实验室进化，培养基组成和发酵条件将用于产生高性能菌株的强化制剂。发酵产物将在水稻植株上进行促生长性能试验。一旦植物被定植，细菌就不受外部环境的影响，这意味着它们可以形成一季的共生关系，植物将有效地利用大气中的氮来生长发育。据报道，这种技术每年在其主作物中每公顷提供200公斤氮——足以满足大多数主要集约化种植谷物的需求——有可能在全球范围内减少世界对破坏环境的合成氮肥的依赖。

Soil fertilization is a key factor for agriculture with nitrogen being the most limiting nutrient for crop productivity. As a critical component for proteins, DNA and chlorophyll, nitrogen is essential for healthy plant growth and development. Half the world's human population currently relies on the Haber-Bosch process to produce synthetic nitrogen fertilizer (SNF). However, 1% of all fossil fuel production is consumed to generate SNF. That cost in CO2 is significant but dwarfed by the second-order effects of the fertilizer, which has only 30-50% efficacy. The remainder enters watercourses as nitrate pollution or is released into the air as nitrous oxide, causing massive environmental damage and human health problems.NetZeroNitrogen (NZN) exists to eliminate synthetic nitrogen fertilizer's estimated 1.1 billion tonnes of CO2e annual contribution to global warming by providing farmers with a highly effective, natural, cheaper alternative to synthetic fertilizer. With a focus on a particularly interesting plant growth-promoting endophytic diazotrophic bacterium with great agronomic potential, our innovation is in building a platform of characterised strain biodiversity to develop highly optimised inoculation formulations for specific crops and environmental conditions. Evaluating the full range of PGP activities (across a library of \>30 strains) has never yet been undertaken anywhere in the world for this bacteria.This project funds the development of a prototype biofertilizer product that will lead to robust, reliable and high levels of colonization of internal tissues in crop plants by the NZN bacteria. Using world-class precision fermentation facilities at the University of Nottingham, the optimization of bacterial cell pre-conditioning for six elite strains will be identified using proprietary colonization assays developed by NZN scientists. Adaptive laboratory evolution, culture media composition and fermentation conditions will then be used to generate enhanced preparations of high-performing strains. The resultant products of fermentation will be tested for their plant growth-promoting performance in rice plants.Once plants are colonized, the bacteria are protected from the external environment meaning they can form season-long symbiotic relationships, and the plants will effectively be able to use the atmospheric nitrogen for their growth and development. Reported to provide 200 kg nitrogen per hectare each year in its host crop - an amount sufficient to satisfy demand in most major intensively-grown cereals - this technology has the potential to impact on a global scale to reduce the world's reliance on environmentally damaging synthetic nitrogen fertilizers.