Mixtures of Pseudomonas putida CECT 5279 cells of different ages: optimization as biodesulfurization catalyst.

摘要

Sulfur contentinfossilfuelsisknowntobethemostimportantanthropogeniccauseofsulfuroxideemissions totheatmosphere.Inordertoavoidhealth,environmentalandtechnicalproblemscausedby thiscompound,legislationimposesrestrictivelimitationstofuelsulfurcontent.Biodesulfurization(BDS) canbecomeacomplementarytechnologytohydrodesulfurization(HDS)tofacethissituation.Pseudomonas putida CECT 5279isageneticallymodifiedmicroorganismwhichcanactasadesulfurizingbiocatalyst. Thismicroorganismhastheabilityofperformingthemetabolic4Spathwayfrom Rhodococcuserythropolis IGTS8, inordertodesulfurizeDBT,asamodelcompound.Maximum in vivo activities ofmonooxygenase enzymes(DszAandDszC)areshownwhenlateexponentialgrowthphaseisreached(23 h),whiledesulfinaseenzymeDszBpresentsamaximumactivityduringtheearlyexponentialgrowthphase (5h),aspreviouslyreported [1]. Also,ithasbeenprovedthatthecombinedutilizationofthesetwocell agesyieldsexcellentresultswhenusedasbiocatalystfordesulfurization [2]. Theaimofthisworkisto optimizetheratioandtotalbiomassconcentrationofboth5hand23hgrowthtimecellsinacomplexbiocatalyst fordesulfurizationbyperformingrestingcellsbiodesulfurizationassaysusingdibenzothio-phene (DBT)assulfurmodelcompound.Thebestcombinationofcellswasdeterminedaimingforthehighest desulfurizationintheshortesttimeofoperationwhileinvestingtheminimumconcentrationofbiomass. Aparticularcellmixture,containing66.7%of23hgrowthtimecells,wasfoundtoworkasthemost effectivedesulfurizationbiocatalyst.