Lipid production by fungus Mortierella isabellina

Mikrobni lipidi su alternativna sirovina za proizvodnju biodizela druge generacije. Mortierella isabellina uzgojena je u hranjivoj podlozi uz različite molarne omjere izvora ugljika i dušika (C:N). Najveća produktivnost sinteze biomase bez lipida od 0,0285 g L-1 h-1 postignuta je pri omjeru C:N 50-150 mol mol-1. Maksimalni udjel lipida (50 %, g g-1) izmjeren je pri omjerima 150-200 mol mol-1. Kako bi se povećao prinos lipida kultura plijesni uzgojena je šaržnim postupkom uz pritok supstrata u tikvicama i bioreaktoru s miješalom (STR) primjenom dva načina prihrane izvorom ugljika i dušika. U tikvicama kultura je prihranjivana s podlogom u kojoj je omjer C:N bio 10-50 mol mol-1. U STR, kultura je prihranjivana s glukozom tako da je koncentracija dodane glukoze iznosila 40 g L-1. pH kulture održavan je dodatkom amonijaka koji je služio i kao izvor dušika za rast stanica. Primjenom ove strategije prihrane postignuta je velika produktivnost sinteze biomase bez lipida od 0,304 g L h-1 i vrlo mala produktivnost biosinteze lipida.Microbial lipids are an alternative feedstock for production of second generation biodiesel. Mortierella isabellina was cultivated in a medium at different carbon to nitrogen molar ratios (C:N). The highest productivity of lipid-free biomass of 0,0285 g L-1 h-1 was occurred at an initial C:N ratio of 50-150 mol mol-1. Maximal lipid content of 50 % (wt/wt) was obtained at C:N ratio of 150-200 mol mol-1. In order to improve lipid yield, the fungus was grown in a fed-batch cultures in shake flasks and stirred tank reactor (STR) applying two feeding strategies with carbon and nitrogen source. In shake-flasks experiment the culture was fed with media at 10-50 mol mol-1 C:N ratio. In STR, the culture was fed by glucose to give 40 g L-1. pH was maintained using ammonia, which was also used as a nitrogen source for cell growth. Using fed batch strategy, high productivity of lipid free-biomass of 0,304 g/L/h and low lipid productivity was obtained