Kamat Siya, Kumari Madhuree, Sajna Kuttuvan Valappil, Singh Sandeep Kumar, Kumar Ajay, Jayabaskaran C
Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
Celignis Biomass Analysis Laboratory, V94 7Y42 Limerick, Ireland.
Microorganisms. 2023 Apr 12;11(4):999. doi: 10.3390/microorganisms11040999.
Flavonoids encompass a heterogeneous group of secondary metabolites with exceptional health benefits. Chrysin, a natural dihydroxyflavone, possesses numerous bioactive properties, such as anticancer, antioxidative, antidiabetic, anti-inflammatory, etc. However, using traditional sources of chrysin involves extracting honey from plants, which is non-scalable, unsustainable, and depends on several factors, including geography, climatic conditions, and the season, which limits its production at a larger scale. Recently, microbial production of desirable metabolites has garnered attention due to the cost-effectiveness, easy scale-up, sustainability, and low emission of waste. We previously reported for the first time the chrysin-producing marine endophytic fungus , associated with a marine green alga. To extend our understanding of chrysin biosynthesis in in the present study, we have assessed the presence of flavonoid pathway intermediates in extracts using LC-MS/MS. The presence of several key metabolites, such as dihydrokaempferol, chalcone, galangin, baicalein, chrysin, p-Coumaroyl-CoA, and p-Cinnamoyl-CoA, indicates the role of flavonoid biosynthesis machinery in the marine fungus. Further, we have aimed to enhance the production of chrysin with three different strategies: (1) optimizing the fermentation parameters, namely, growth medium, incubation time, pH, and temperature; (2) feeding key flavonoid pathway intermediates, i.e., phenylalanine and cinnamic acid; (3) elicitation with biotic elicitors, such as polysaccharide, yeast extract, and abiotic elicitors that include UV radiation, salinity, and metal stress. The combined effect of the optimized parameters resulted in a 97-fold increase in the chrysin yield, resulting in a fungal cell factory. This work reports the first approach for enhanced production of chrysin and can serve as a template for flavonoid production enhancement using marine endophytic fungi.
黄酮类化合物是一类具有特殊健康益处的次生代谢产物的异质群体。白杨素是一种天然二羟基黄酮，具有多种生物活性，如抗癌、抗氧化、抗糖尿病、抗炎等。然而，使用传统的白杨素来源需要从植物中提取蜂蜜，这是不可扩展、不可持续的，并且取决于包括地理、气候条件和季节在内的几个因素，这限制了其大规模生产。最近，由于成本效益、易于扩大规模、可持续性和低废物排放，通过微生物生产所需代谢产物受到了关注。我们之前首次报道了与一种海洋绿藻相关的产白杨素的海洋内生真菌。为了在本研究中扩展我们对白杨素生物合成的理解，我们使用液相色谱-串联质谱法评估了提取物中黄酮类途径中间体的存在。几种关键代谢产物的存在，如二氢山奈酚、查耳酮、高良姜素、黄芩素、白杨素、对香豆酰辅酶A和对肉桂酰辅酶A，表明了黄酮类生物合成机制在海洋真菌中的作用。此外，我们旨在通过三种不同策略提高白杨素的产量：（1）优化发酵参数，即生长培养基、培养时间、pH值和温度；（2）添加关键黄酮类途径中间体，即苯丙氨酸和肉桂酸；（3）用生物诱导剂如多糖、酵母提取物以及包括紫外线辐射、盐度和金属胁迫在内的非生物诱导剂进行诱导。优化参数的综合作用使白杨素产量提高了97倍，从而形成了一个真菌细胞工厂。这项工作报道了提高白杨素产量的第一种方法，并可作为利用海洋内生真菌提高黄酮类化合物产量的模板。
