The Study Of Producing Astaxanthin By Fermentation Method

As a singular antioxidant agent, astaxanthin became the reseach focus. But that producingastaxanthin by fermentation method was restricted by low yield, strict condition and high cost.We studied a Rhodothece glutinis isolated from sea mud in present study. By analysis, weidentified this Rhodothece glutinis is a kind of high carotenoid producer, and the main pigmentis astaxanthin. Through optimization of culture condition, we construct a two stage temperaturemethod. In experiment, this method was authenticated to rise the yield of astaxanthin to20%.Through UV mutation breeding we got a stable forward mutation of this Rhodotheceglutinis. We studied the effect of ingredients, such as ammonium citrate、 maizena、tomatoextractive，which are rich in precursor of astaxanthin on astaxanthin production. We alsooptimized the medium of this Rhodothece glutinis, the biomass and astaxanthin production wasrised to1.31×10~9CFU/ml and9.41μg/ml. Through fed batch cultivation, both biomass andastaxanthin production were raised. Continuity fed batch cultivation is better than intermittencefed batch cultivation. Astaxanthin yield was raised to17.03μg/ml.We also isolated a Bacillus licheniformis from sea mud. This Bacillus licheniformis coulddegradatiohn prawn shell quickly, then astaxanthin was liberated.Extracted by alcohol,astaxanthin was gotten. The yield was59.775μg per gram shell. Compared with orthodoxmethods, this method had visible advance. It not only reduced the cost, but also rised extractionefficiency and reduced pollution.Results form present study showed that, prawn shell degradation product could be aningredient of Rhodothece glutinis medium. In this way, we could extract astaxanthin fromprawn shell, but also provide medium for Rhodothece glutinis which produce astaxanthin. Thismethod cut down the cost of Rhodothece glutinis medium, provides extra astaxanthin andmakes two different way of producing astaxanthin be one.