Effect Of Fatty Acids On MVA Pathway

MVA pathway is very important for organism. The main product ofMVA pathway is terpenoids, which includes ergosterol, CoQ,beta-carotene and astaxanthin, etc. These products can participate in thesynthesis of cell membranes, transfer electron in respiratory chain andadjust cellular redox potential. Produced through fermentation, CoQ canbe used as medical and health food, beta-carotene and astaxanthin arealready widely used as additions in foods. There is a good marketprospect of producing end products of MVA pathway throughmicroorganism fermentation.Fatty acid is another essential part of cell, it can participate in thesynthesis of cell membranes, decompose as carbon resource to provideacetyl-CoA and energy, even participate in cell signal transduction inplants and insects. The substrate of fatty acid synthesis is acetyl-CoA, thesame as MVA pathway, so they may influence each other at substratelevel. Some multi-unsaturated fatty acid (MUFA) can regulate the synthesis of reducing substance by increase the oxidative stress. Becausefatty acids take a large proportion of cells and are relatively cheap, if therelationship between fatty acid and MVA pathway is revealed, it will notonly bring huge economic benefits, but also clear the position of fattyacid in organisms, and provide evidence for the evolution of someimportant metabolic processes, even offer treatment for diseases relatedto MVA pathway or fatty acid metabolism.This research added7fatty acids, including oleic acid, linoleic acid,stearic acid, etc., to Rhodotorula glutinis As2.102, Pichia pastoris Gs115,Candida tropicalis, Saccharomyces cerevisiae and Blakeslea trispora.Final products of MVA pathway are measured, and the trends ofintermediates after adding fatty acids are studied. We proved that:(1) The utilization of fatty acids in different strains exists preference,it can be related to the composition of their cell membrane.(2) MUFAs'regulation on MVA pathway is mainly by increasing theoxidative stress. There is a diversity of the MUFA utilization in differentstrains because of their oxidation tolerance difference, but the preferenceisn't arranged by the MUFAs' degree of unsaturation.(3) For most fatty acids that can promote cell growth, it remainseffective no matter the fatty acids are added with a high concentration ora low one, and usually a low concentration addition will perform better. Itindicates that the fatty acids play as carbon resource to provide more substrate for MVA pathway maybe is just a minor mechanism.(4) Fatty acids can regular the metabolic flow of acetyl-CoA andincrease the metabolic flux of MVA pathway through several ways, suchas participate in the synthesis of cell membrane to decrease the demand offatty acid synthesis, provide additional acetyl-CoA though beta-oxidation,and some can inhibit the synthesis of fatty acids by feedback inhibition.(5) There is a diversity on the utilization of straight chain saturatedfatty acids. Some fatty acids even have cytotoxicity, but the degree of thetoxicity is strain varied.(6) Some fatty acids, such as alpha-linolenic acid, may regulate theactivity of some enzymes in MVA pathway, which will lead to theincrease of certain product.