Junker Nora, Sariyar Akbulut Berna, Wendisch Volker F
Genetics of Prokaryotes, Faculty of Biology and Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany.
Department of Bioengineering, Marmara University, Istanbul, Türkiye.
Front Bioeng Biotechnol. 2024 Jul 10;12:1419444. doi: 10.3389/fbioe.2024.1419444. eCollection 2024.
Oranges are the most processed fruit in the world-it is therefore apparent that the industrial production of orange juice generates large quantities of orange peel as a by-product. Unfortunately, the management of the orange peel waste leads to economic and environmental problems. Meanwhile, the use of sustainable raw materials for the production of bulk chemicals, such as amino acids, is becoming increasingly attractive. To address both issues, this study focused on the use of orange peel waste as a raw material for media preparation for the production of amino acids by engineered . grew on pure orange peel hydrolysate (OPH) and growth was enhanced by the addition of a nitrogen source and a pH buffer. Inhibitory effects by the combination of high concentrations of OPH, (NH)SO, and MOPS buffer in the wild-type strain (WT), were overcome in the tyrosine-producing engineered strain AROM3. Genetic modifications that we identified to allow for improved growth rates under these conditions included the deletions of the vanillin dehydrogenase gene , the ʟ-lactate dehydrogenase gene and the 19 genes comprising cluster cg2663-cg2686. A growth inhibiting compound present in high concentrations in the OPH is 5-(hydroxymethyl)furfural (HMF). We identified as being primarily responsible for the oxidation of HMF to its acid 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), as the formation of HMFCA was reduced by 97% upon deletion of in WT. In addition, we showed that growth limitations could be overcome by adjusting the media preparation, using a combination of cheap ammonia water and KOH for pH neutralization after acidic hydrolysis. Overall, we developed a sustainable medium based on orange peel waste for the cultivation of and demonstrated the successful production of the exemplary amino acids ʟ-arginine, ʟ-lysine, ʟ-serine, ʟ-valine and ʟ-tyrosine.
橙子是世界上加工最多的水果——因此很明显，橙汁的工业生产会产生大量作为副产品的橙皮。不幸的是，橙皮废料的管理会导致经济和环境问题。与此同时，使用可持续原料生产大宗化学品，如氨基酸，正变得越来越有吸引力。为了解决这两个问题，本研究聚焦于将橙皮废料用作工程菌生产氨基酸的培养基制备原料。[工程菌名称]在纯橙皮水解物（OPH）上生长，添加氮源和pH缓冲剂可促进生长。野生型菌株（WT）中高浓度的OPH、硫酸铵（(NH)₂SO₄）和MOPS缓冲剂组合产生的抑制作用，在生产酪氨酸的工程菌[工程菌名称]菌株AROM3中得以克服。我们确定在这些条件下能提高生长速率的基因改造包括香草醛脱氢酶基因[基因名称]、L-乳酸脱氢酶基因[基因名称]以及包含cg2663 - cg2686簇的19个基因的缺失。OPH中高浓度存在的一种生长抑制化合物是5-(羟甲基)糠醛（HMF）。我们确定[酶名称]主要负责将HMF氧化为其酸5-羟甲基-2-呋喃羧酸（HMFCA），因为在WT中缺失[基因名称]后，HMFCA的形成减少了97%。此外，我们表明通过调整培养基制备方法可以克服生长限制，即在酸性水解后使用廉价的氨水和氢氧化钾组合进行pH中和。总体而言，我们开发了一种基于橙皮废料的可持续培养基用于[工程菌名称]的培养，并证明成功生产了示例性氨基酸L-精氨酸、L-赖氨酸、L-丝氨酸、L-缬氨酸和L-酪氨酸。
