BRC-BIO: Bioconversion of Food Waste with Non-model Organisms

全球每年有2.86万亿磅的食物被浪费。仅美国就浪费了大约2000亿英镑，这造成了2400亿美元的收入损失，相当于总粮食供应的30%-40%。这些废物最终进入垃圾填埋场，造成33亿吨温室气体排放。为了减少浪费和温室气体，这项研究建议将食物垃圾转化为2，3-丁二醇和其他有价值的最终产品。食物垃圾将从田纳西州纳什维尔的小学和中学收集，以评估其在生物产品生产中的潜力，同时也提高年轻、代表不足的未来科学家的意识和参与。从学校收集的食物垃圾样本将进行营养成分、分类方法和储存条件的分析。这些结果将有助于确定未来收集食物垃圾的最佳方法。为了将食物垃圾转化为有价值的化合物，将在食物垃圾中添加耐热细菌，以利用自然发生的微生物发酵。当培养温度提高到约50°C时，独特的耐热细菌可以胜过食物垃圾中发现的其他污染微生物，这样，食物垃圾将不需要灭菌，从而降低转化成本和对环境的影响。总体而言，这项研究将解决现有的知识差距，并有助于提供一种将食物垃圾转化为生物制品的有效手段。该项目还将为本科生提供教育和研究机会。该项目的主要目标是将未经灭菌的食物垃圾转化为有价值的生物制品，通过“开放式”嗜热发酵。利用食物垃圾生产生物制品的主要问题之一是不可预测的异质性和不一致的性质。虽然食物垃圾确实含有用于微生物发酵的高能大分子，但通过食物垃圾修复来维持潜在的生物经济需要稳定的原料。限制食物垃圾使用的另一个问题是与消毒相关的成本。要去除本地污染微生物，必须采用灭菌方法(如高压蒸汽)。然而，为了跳过这些过程，抑制本地微生物，提出了一种新的地衣芽孢杆菌YNP5-TSU高温发酵方法。除了这种方法外，还将在黄石国家公园内收集新的嗜热微生物和温泉的元基因组测序，以产生新的耐热酶和/或微生物，这些酶和/或微生物可用于改善目前的嗜热食物垃圾转化。这项研究的有效性将影响未来将食物垃圾作为可持续饲料的努力。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Each year 2.86 trillion pounds of food is wasted globally. The U.S. alone wastes approximately 200 billion pounds, which accounts for $240 billion in revenue loss, equal to 30-40% of the total food supply. This waste ends up in landfills, contributing to 3.3 gigatons of greenhouse gas emissions. To reduce waste and greenhouse gases, this research proposes the conversion of food waste to 2,3-butanediol and other valuable end-products. Food waste will be collected from Elementary and Middle Schools within the Nashville, TN Metro Public Schools District to evaluate its potential in bioproduct production, while also increasing awareness and participation from young, underrepresented future scientists. Food waste samples collected from schools will be analyzed with regards to nutrient composition, sorting methods, and storage conditions. These results will help determine the best methods for collecting food waste in the future. To carry-out conversion of food waste to valuable compounds, heat-stable bacteria will be added to food waste to take advantage of naturally occurring microbial fermentation. Unique heat-tolerant bacteria can outcompete other contaminant microbes found in food waste when incubation temperatures are increased to approximately 50 °C. In doing so, food waste will not require sterilization, reducing the cost of conversion and the impact on the environment. Overall, this study will address the existing knowledge gap and help to provide an efficient means of converting food waste to bioproducts. The project will also provide educational and research opportunities for undergraduate students.The major goal of this project is to convert non-sterile food waste into valuable bioproducts through “open” thermophilic fermentation. One of the major concerns of using food waste for bioproduct production is the unpredictable heterogeneity and inconsistent nature. While food waste does contain high energy macromolecules for microbial fermentation, a consistent feedstock is needed to sustain a potential bioeconomy through food waste remediation. Another issue limiting the usage of food waste is the cost associated with sterilization. To remove native contaminant microorganisms, sterilization methods (e.g., high-pressure steam) must be carried out. However, to skip these processes and suppress native microbes, a novel high-heat fermentation method with Bacillus licheniformis YNP5-TSU is proposed. In addition to this approach, collections of new thermophilic microorganisms and metagenomic sequencing of hot springs, within Yellowstone National Park, will be conducted to yield novel heat stable enzymes and/or microorganisms that can be used to improve current thermophilic food waste conversion. The effectiveness of this study will impact future endeavors to use food waste as a sustainable feedstock.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.