Optimizing the production of biosurfactants from marine bacteria for applications in personal care sector

2022年5月起的新计划：生物表面活性剂是两亲性化学品，几乎用于现代工业的每个部门。然而，它们主要是通过使用化石燃料前体的化学合成来生产的，因此这些化学品通常具有生态毒性和不可生物降解的特点。生产生物表面活性剂的微生物为这些化学物质提供了更可持续、无毒和环保的来源。本项目将重点研究海洋细菌生产的生物表面活性剂，其中鼠李糖脂是一类糖脂，由一个或两个鼠李糖基团连接到一个或两个脂肪酸链上。铜绿假单胞菌已经很好地表征了鼠李糖脂的生产，但将这些化合物推向市场的主要限制通常与生产生物的致病性有关-即铜绿假单胞菌是鼠李糖脂的主要来源，但这种生物是致病性的。其他非假单胞菌生物也能产生鼠李糖脂，但它们也具有致病性，或者在某些条件下也会致病。因此，已经有许多关于鉴定具有合成非致病性鼠李糖脂潜力的微生物的研究。该项目将探索在非致病性海洋细菌菌株中合成生物表面活性剂，包括鼠李糖脂，并尝试使用合成生物学方法和通过操纵发酵条件进一步优化来提高这些化合物的产量，以便生产足够数量的工业用途。原始节目：回收、再循环、再工程：解决废轮胎问题的微生物和生物技术解决方案废旧橡胶轮胎，特别是被填埋的轮胎，已被公认为迅速成为世界上最重要的环境废物问题之一。橡胶的回收是一项非常具有挑战性的任务，到目前为止，还没有解决这个日益重要的问题。工业合作伙伴recycle有限公司开发了一种新的可持续技术，利用微生物将橡胶废料脱硫化并再利用，再加工成高价值的橡胶产品。橡胶的脱硫作用依赖于酶的作用，而酶的作用尚未完全确定。这个博士项目将研究橡胶生物脱硫的关键过程。博士研究生将接受尖端技术的培训，以分析和识别负责生物脱硫的所有基因和酶，以便更好地理解和进一步改进脱硫过程。该项目还将致力于从轮胎垃圾场富集和分离新的脱硫细菌，并挖掘降解有机硫化合物的新基因。此外，学生将利用定点诱变来创建组成表达这些脱硫酶的细菌突变株。

New programme as from May2022:Biosurfactants are amphiphilic chemicals used in almost every sector of modern industry. However, they are mainly produced by chemical synthesis using fossil fuel-based precursors, and as such these chemicals are often characterized as eco-toxic and non-biodegradable. Biosurfactant-producing microorganisms offer a much more sustainable, non-toxic, and eco-friendly source for these chemicals. This project will focus on biosurfactants produced by marine bacteria, with a focus on rhamnolipids, which are a class of glycolipids consisting of one or two rhamnose sugar groups attached to one or two fatty acid chains. Rhamnolipid production has been well characterized in Pseudomonas aeruginosa, but a major limitation in getting these compounds to market is often associated with the pathogenicity of the producing organism - i.e. Pseudomonas aeruginosa which is the main source of rhamnolipids, but this organism is pathogenic. Other non-Pseudomonas organisms have been found to produce rhamnolipids, but they too are pathogenic or can become so under certain conditions. As such, there have been numerous studies on identifying microorganisms with the potential to synthesize rhamnolipids that are non-pathogenic. This project will explore the synthesis of biosurfactants, including rhamnolipids, in non-pathogenic strains of marine bacteria, and attempt to enhance the production of these compounds using synthetic biology approaches and further optimization by manipulation of fermentation conditions in order to produce sufficient quantities for industrially use.Original programme: Recover, Recycle, Reengineer: A microbial and biotechnological solution to tackle the waste tyre problemUsed rubber tyres, particularly when disposed to landfill, have been recognised to fast becoming one of the foremost environmental waste problems in the world. The recycling of rubber is a very challenging task and to date there is no solution to this increasingly important problem. The industrial partner Recircle Ltd has developed a novel sustainable technology to devulcanise and reuse rubber waste for reprocessing into high value rubber products using microorganisms. The devulcanisation/desulfurisation of rubber relies on the work of enzymes which are not fully identified yet. This PhD project will investigate the key processes involved in biodesulfurisation of rubber. The PhD student will be trained in cutting-edge techniques to analyse and identify all genes and enzymes that are responsible for biodesulfurisation in order to get a better understanding and further improve the devulcanisation process. This project will also aim to enrich and isolate new desulfurising bacteria from tyre dump sites and mine for novel genes in the degradation of organosulfur compounds. In addition, the student will utilise site-directed mutagenesis to create mutant strains of the bacteria that constitutively express these desulfurisation enzymes.