Research Of D-arabitoI Production By Osmophilic Yeast

D-arabitol is a kind of natural functionality five carbon alcohol which mainly existed inlichens and mushrooms, it is one of the12Top Value Added Chemicals from Biomassannounced by U.S. Department of Energy, and is widely used in food, medicine, and industryfield.D-arabtiol as a high value added chemicals draw more and more attention, meanwhile,zymotechnics as an environmentally friendly and economically feasible way for D-arabitolproduction attracted more and more interest.In this research, we treated osmoadaptation yeast SFA-S1with UV, DES, and UV-DEScompound mutation, and via flat and shake flask screening, we finally obtained a mutantstrain UD-3with a D-arabitol yield of32.3g/L, furthermore we optimized the medium andculture condition of UD-3.Single-factor experiments indicted that there were six factors which had significantinfluence on D-arabitol yield of mutant strain UD-3. These six factors respectively wereglucose, yeast extract, peptone, ammonium sulfate, copper sulfate, zinc sulfate and corn steepliquor.To screen out the main factors influencing the D-arabitol yield of mutant strain andfigure out the interaction between them, we used RSM to optimize the fermentation mediumof mutant strain any further.Plackett-Burman experiment showed that yeast extract, ammonium sulfate, zinc sulfatewere the most significant factors of D-arabitol yield with high reliability. We utilized a designof three factors three levels with Box-Behnken design principle, and finally obtained aoptimized culture medium consisted of glucose200g/L, yeast extract4.05g/L, ammoniumsulfate3.33g/L, zinc sulfate1.21g/L, corn steep liquor2.5g/L, copper sulfate0.20g/L. Withthis culture medium, the D-arabitol yield of mutant strain reached to46.67g/L.During verification test, the D-arabitol yield displayed an average value of46.62g/Lwhich was similar to the predicted value. Compared with Initial culture, the D-arabitol yieldof mutant strain increased44.3%with the optimized culture.The result of cultural condition optimization showed that the optimum culture condition under this experiment condition was as follows: culture time of seed18h, inoculum volume2%, culture temperature28℃and revolving speed180r/min.Attempting to get further improvement of D-arabitol yield, we studied the influence ofdifferent additives on D-arabitol yield, and it turned out that adding n-dodecane as carrier ofoxygen, pyrithioxine hydrochloride as enzyme activity promoter of glucose-6-phosphatedehydrogenase, amphotericin B which affected the cellular membrane permeability and H2O2all could improve the production of D-arabitol, and their optimal quantity in this researchseparately was2%,0.15%,2.55mg/L and0.03%, but the addition of iodoacetic acid as wellas NaF inhibited the Synthesis of D-arabitol, and the using of NaCl, PEG and erythritol as theosmotic pressure regulator all reduced the production of D-arabitol.