Lomascolo Anne, Odinot Elise, Villeneuve Pierre, Lecomte Jérôme
Aix Marseille Univ., INRAE, UMR1163 BBF Biodiversité et Biotechnologie Fongiques, 13009, Marseille, France.
OléoInnov, 19 rue du Musée, 13001, Marseille, France.
Biotechnol Biofuels Bioprod. 2023 Nov 14;16(1):173. doi: 10.1186/s13068-023-02425-w.
p-Hydroxycinnamic acids, such as sinapic, ferulic, p-coumaric and caffeic acids, are among the most abundant phenolic compounds found in plant biomass and agro-industrial by-products (e.g. cereal brans, sugar-beet and coffee pulps, oilseed meals). These p-hydroxycinnamic acids, and their resulting decarboxylation products named vinylphenols (canolol, 4-vinylguaiacol, 4-vinylphenol, 4-vinylcatechol), are bioactive molecules with many properties including antioxidant, anti-inflammatory and antimicrobial activities, and potential applications in food, cosmetic or pharmaceutical industries. They were also shown to be suitable precursors of new sustainable polymers and biobased substitutes for fine chemicals such as bisphenol A diglycidyl ethers. Non-oxidative microbial decarboxylation of p-hydroxycinnamic acids into vinylphenols involves cofactor-free and metal-independent phenolic acid decarboxylases (EC 4.1.1 carboxyl lyase family). Historically purified from bacteria (Bacillus, Lactobacillus, Pseudomonas, Enterobacter genera) and some yeasts (e.g. Brettanomyces or Candida), these enzymes were described for the decarboxylation of ferulic and p-coumaric acids into 4-vinylguaiacol and 4-vinylphenol, respectively. The catalytic mechanism comprised a first step involving p-hydroxycinnamic acid conversion into a semi-quinone that then decarboxylated spontaneously into the corresponding vinyl compound, in a second step. Bioconversion processes for synthesizing 4-vinylguaiacol and 4-vinylphenol by microbial decarboxylation of ferulic and p-coumaric acids historically attracted the most research using bacterial recombinant phenolic acid decarboxylases (especially Bacillus enzymes) and the processes developed to date included mono- or biphasic systems, and the use of free- or immobilized cells. More recently, filamentous fungi of the Neolentinus lepideus species were shown to natively produce a more versatile phenolic acid decarboxylase with high activity on sinapic acid in addition to the others p-hydroxycinnamic acids, opening the way to the production of canolol by biotechnological processes applied to rapeseed meal. Few studies have described the further microbial/enzymatic bioconversion of these vinylphenols into valuable compounds: (i) synthesis of flavours such as vanillin, 4-ethylguaiacol and 4-ethylphenol from 4-vinylguaiacol and 4-vinylphenol, (ii) laccase-mediated polymer synthesis from canolol, 4-vinylguaiacol and 4-vinylphenol.
对羟基肉桂酸,如芥子酸、阿魏酸、对香豆酸和咖啡酸,是植物生物质和农业工业副产品(如谷物麸皮、甜菜和咖啡果肉、油籽粕)中含量最丰富的酚类化合物之一。这些对羟基肉桂酸及其脱羧产物乙烯基酚(油菜籽酚、4-乙烯基愈创木酚、4-乙烯基苯酚、4-乙烯基儿茶酚)是具有多种特性的生物活性分子,包括抗氧化、抗炎和抗菌活性,以及在食品、化妆品或制药行业的潜在应用。它们还被证明是新型可持续聚合物的合适前体,以及双酚A二缩水甘油醚等精细化学品的生物基替代品。对羟基肉桂酸非氧化微生物脱羧生成乙烯基酚涉及无辅因子和无金属的酚酸脱羧酶(EC 4.1.1羧基裂解酶家族)。历史上,这些酶是从细菌(芽孢杆菌属、乳杆菌属、假单胞菌属、肠杆菌属)和一些酵母(如酒香酵母或假丝酵母)中纯化得到的,它们分别用于将阿魏酸和对香豆酸脱羧生成4-乙烯基愈创木酚和4-乙烯基苯酚。催化机制包括第一步,即对羟基肉桂酸转化为半醌,然后在第二步中自发脱羧生成相应的乙烯基化合物。通过阿魏酸和对香豆酸的微生物脱羧合成4-乙烯基愈创木酚和4-乙烯基苯酚的生物转化过程,历史上吸引了最多的研究,使用的是细菌重组酚酸脱羧酶(特别是芽孢杆菌属的酶),迄今为止开发的过程包括单相或双相系统,以及使用游离或固定化细胞。最近,研究表明,鳞皮扇菇属的丝状真菌天然产生一种更通用的酚酸脱羧酶,除了其他对羟基肉桂酸外,对芥子酸也具有高活性,这为通过应用于菜籽粕的生物技术过程生产油菜籽酚开辟了道路。很少有研究描述这些乙烯基酚进一步微生物/酶促生物转化为有价值的化合物:(i)从4-乙烯基愈创木酚和4-乙烯基苯酚合成香草醛、4-乙基愈创木酚和4-乙基苯酚等香料,(ii)由油菜籽酚、4-乙烯基愈创木酚和4-乙烯基苯酚进行漆酶介导的聚合物合成。