Using precision fermentation to optimize biofertilizer preparation

土壤肥力是农业的关键因素，而氮素是限制作物生产力的最重要的养分。氮是蛋白质、DNA和叶绿素的重要组成部分，对植物的健康生长发育至关重要。目前，世界上一半的人口依靠哈伯-博世工艺生产合成氮肥(SNF)。然而，所有化石燃料生产的1%被消耗在生产SNF上。二氧化碳的成本是巨大的，但与化肥的二阶效应相比就相形见绌了，后者只有30%-50%的效果。其余的以硝酸盐污染或以一氧化二氮的形式排放到空气中，造成大规模的环境破坏和人类健康问题。NetZeroNitgen(NZN)的存在是为了消除合成氮肥每年约11亿吨二氧化碳对全球变暖的贡献，为农民提供一种高效、天然、廉价的合成肥料替代品。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，具有巨大的农学潜力，我们的创新之处在于建立了一个具有特色的菌株生物多样性平台，以开发针对特定作物和环境条件的高度优化的接种配方。对PGP活性的全面评估(在30个菌株的文库中)在世界上还从未对这种细菌进行过。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细菌在作物体内组织的强健、可靠和高水平的定植。使用诺丁汉大学世界级的精密发酵设施，将使用NZN科学家开发的专有定植分析来确定六个精英菌株的细菌细胞预适应的优化。然后，将使用适应性的实验室进化、培养基组分和发酵条件来产生高效菌株的强化制剂。发酵产物将在水稻植株中测试其促进植物生长的性能。一旦植物被定植，细菌就会受到外部环境的保护，这意味着它们可以形成长达一季的共生关系，植物将能够有效地利用大气中的氮来生长和发育。据报道，这项技术每年在寄主作物中每公顷提供200公斤氮--足以满足大多数主要集约种植谷物的需求--有可能在全球范围内产生影响，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.