Biotranformations of natural and inexpensive platform feedstocks to high added value flavour compounds

将天然且廉价的平台原料生物转化为高附加值风味化合物

• 批准号: BB/N010507/1
• 负责人: Georgios Koutsidis
• 金额: $ 12.95万
• 依托单位: Northumbria University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FN010507%2F1
• 关键词: Biotranformations; natural; inexpensive; platform; feedstocks

The project focuses on the biocatalysis of relatively inexpensive and abundant natural monoterpenes using previously derived enzyme panels of P450s and KREDS. In particular, alpha pinene (75-90% of turpentine oil) could be transformed to verbenol, verbenone, myrtenol and myrtenal while beta-pinene could be transformed to pinocarveol and pinocarvone. Verbenol and verbenone have been previously produced in microbial systems with black yeast (Hormonema sp) or Aspergilus niger. However, those processes have not been commercialized due to, in the first case interferences with the metabolism of the microorganism and in the latter the commercially non-viable yields. (R)-Limonene is another inexpensive natural monoterpene that has been used as the starting material in the chemical synthesis of carvone, a key volatile compound of caraway seeds, dill seeds and spearmint. Such chemical synthesis could be replaced by biocatalysis using P450s and KRED panels. Other inexpensive naturally derived feedstocks include terpinolene, delta-3-carene, caryophyllene and a-terpineol. Of particular interest is the production of beta-caryophyllene alcohol, a major constituent of all spice, and caryophyllene oxide from beta-caryophyllene as well as carveol from alpha-terpineol. Other approaches will focus on the production of linear terpenals from the corresponding terpenes for example alpha-sinensal from farnesene. The latter is a relatively expensive starting material, however currently there is no other process for the commercial production of sinensal other than distillation from essential oils that contain low amounts of the compound. Carotenoids have been linked with the formation of a number of volatile compounds in plants (i.e beta ionone, (alpha, beta) damascone, damascenone etc), however, very few studies exist that make use of such feedstocks for the production of flavour molecules. It is known that carotenoids could be degraded by exoenzymes of certain fungi and yeasts leading to the formation of flavour compounds. Trametes versicolor, Marasmius scorodonius and Ischnoderma benzoinum have been shown to result in carotene degradation of 93-98 % while the most abundant flavour volatile identified was beta-ionone (up to 10% conversion). More recently a series of carotenoid cleavage dioxygenases (CCDs) have been isolated from a number of sources, including algae. Central cleavage of beta-carotene catalyzed by beta carotene oxygenase 1 yields two molecules of retinaldehyde, while eccentric cleavage of beta carotene at non-central double bonds is catalyzed by other enzymes and can also occur non-enzymatically (through oxidative cleavage with potassium permanganate). VP14 from maize cleaves 9-(Z) epoxy carotenoids specifically at the 11,12 double bond while other regiospecific carotenoid degrading enzymes have recently been characterised in tomato and petunia flowers. Trichosporon asahii, Paenibacillus amylolyticus, Peurotus eryngii as well as Geotrichum sp were also shown to degrade lutein leading to norisoprenoid flavour compounds with 7, 8-dihydro-beta-ionol and beta ionone as the main products. Versatile peroxidases are a novel class of peroxidases which combine the catalytic properties of lignin peroxidase and manganese peroxidase, typically found in Basidiomycetes. Non volatile products of these reactions, apocarotenals and apocarotenones, could also form platform molecules for the production of a number of sesquiterpenes such as alpha and beta sinensal. Most of the above compounds as well as the resulting end products are hydrophobic molecules and relatively prone to oxidation, however, through previous participation in a feasibility project that aimed to produce aldehydes and alcohols from linolenic acid have developed workflows that are also pertinent to this project while 96 well plate fast screening approaches are also routinely employed.

该项目的重点是使用以前衍生的P450和KREDS酶组对相对便宜和丰富的天然单萜进行生物催化。特别地，α-蒎烯（松节油的75-90%）可以转化为马鞭草烯醇、马鞭草烯酮、桃金娘烯醇和桃金娘烯醛，而β-蒎烯可以转化为松香芹醇和松香芹酮。马鞭草烯醇和马鞭草烯酮先前已在具有黑酵母（Hormonema sp）或黑曲霉（Agrobilus尼日尔）的微生物系统中产生。然而，这些方法还没有商业化，因为在第一种情况下干扰微生物的代谢，而在后者中商业上不可行的产率。（R）-柠檬烯是另一种廉价的天然单萜，其已被用作化学合成香芹酮的起始材料，香芹酮是葛缕子种子、莳萝种子和留兰香的关键挥发性化合物。这种化学合成可以用P450和KRED板的生物催化来代替。其它廉价的天然来源的原料包括萜品油烯、δ-3-<$烯、香紫苏烯和α-萜品醇。特别令人感兴趣的是生产β-香紫苏烯醇（所有香料的主要成分）和由β-香紫苏烯制备的香紫苏烯氧化物以及由α-萜品醇制备的香芹醇。其他方法将集中于从相应的萜烯生产线性萜烯，例如从法呢烯生产α-sinensal。后者是相对昂贵的起始材料，然而目前除了从含有少量化合物的精油蒸馏之外，没有其他用于商业生产sinensal的方法。类胡萝卜素与植物中许多挥发性化合物（即β紫罗酮、（α，β）大马酮、异黄酮等）的形成有关，然而，很少有研究利用这些原料生产风味分子。已知类胡萝卜素可以被某些真菌和酵母的胞外酶降解，导致风味化合物的形成。变色栓菌（Trametes versicolor）、小皮伞（Marasmius scorodonius）和Ischnoderma benzoinum已经显示导致93- 98%的胡萝卜素降解，而鉴定的最丰富的风味挥发物是β-紫罗兰酮（高达10%转化率）。最近，一系列类胡萝卜素裂解双加氧酶（CCD）已从许多来源，包括藻类分离。由β-胡萝卜素加氧酶1催化的β-胡萝卜素的中心裂解产生两个分子的视黄醇，而β-胡萝卜素在非中心双键处的偏心裂解由其他酶催化，并且也可以非酶促地发生（通过用高锰酸钾的氧化裂解）。来自玉米的VP 14特异性地在11、12双键处切割9-（Z）环氧类胡萝卜素，而其它区域特异性类胡萝卜素降解酶最近已在番茄和矮牵牛花中表征。Asahii丝孢酵母、Paenibacillusamylolyticus、Pegaserynthium以及Geotrichumsp也显示出降解叶黄素，导致以7，8-二氢-β-紫罗兰醇和β紫罗兰酮为主要产物的去甲异戊二烯风味化合物。多功能过氧化物酶是一类新的过氧化物酶，它联合收割机了木质素过氧化物酶和锰过氧化物酶的催化特性，通常存在于担子菌中。这些反应的非挥发性产物，脱胡萝卜素醛和脱胡萝卜素酮，也可以形成平台分子，用于生产许多倍半萜，如α和β sinensal。大多数上述化合物以及所得终产物是疏水分子并且相对易于氧化，然而，通过先前参与旨在从亚麻酸生产醛和醇的可行性项目，已经开发了与该项目相关的工作流程，同时还常规采用96孔板快速筛选方法。