ABSTRACT
Optimization of a process for extracting astaxanthin from Phaffia rhodozyma by acidic method was investigated, regarding several extraction factors such as acids, organic solvents, temperature and time. Fractional factorial design, central composite design and response surface methodology were used to derive a statistically optimal model, which corresponded to the following optimal condition: concentration of lactic acid at 5.55 mol/L, ratio of ethanol to yeast dry weight at 20.25 ml/g, temperature for cell-disruption at 30 degrees C, and extraction time for 3 min. Under this condition, astaxanthin and the total carotenoids could be extracted in amounts of 1294.7 microg/g and 1516.0 microg/g, respectively. This acidic method has advantages such as high extraction efficiency, low chemical toxicity and no special requirement of instruments. Therefore, it might be a more feasible and practical method for industrial practice.
Subject(s)
Basidiomycota , Chemistry , Hydrochloric Acid , Lactic Acid , XanthophyllsABSTRACT
Fermentation of Phaffia rhodozyma is a major method for producing astaxanthin, an important pigment with industrial and pharmaceutical application. To improve astaxanthin productivity, single factor and mixture design experiments were used to investigate the effects of nitrogen source on Phaffia rhodozyma cultivation and astaxanthin production. Results of single factor experiments showed nitrogen source could significantly affect P. rhodozyma cultivation with respect to carbon source utilization, yeast growth and astaxanthin accumulation. Further studies of mixture design experiments using (NH(4))(2)SO(4), KNO(3) and beef extract as nitrogen sources indicated that the proportion of three nitrogen sources was very important to astaxanthin production. Validation experiments showed that the optimal nitrogen source was composed of 0.28 g/L (NH(4))(2)SO(4), 0.49 g/L KNO(3) and 1.19 g/L beef extract. The kinetic characteristics of batch cultivation were investigated in a 5-L pH-stat fermentor. The maximum amount of biomass and highest astaxanthin yield in terms of volume and in terms of biomass were 7.71 mg/L and 1.00 mg/g, respectively.
Subject(s)
Bioreactors , Microbiology , Cell Culture Techniques , Methods , Cell Proliferation , Computer Simulation , Mitosporic Fungi , Physiology , Models, Biological , Nitrogen , Metabolism , XanthophyllsABSTRACT
Objective To investigate the utility of P504S(?-methylacyl-COA racemase), CK34?E12,p63 and PSA immunohistochemistry in the pathological diagnosis of prostatic adenocarcinoma (PAC).Methods The specimens of 46 cases of PAC,8 cases of prostatic high-grade intraepithelial neo- plasia (HGP1N) and 35 cases of benign prostatic hyperplasia (BPH) tissues were immunohistochemically stained with P504S,CK3413E12,p63 and PSA antibody,respectively.Results Of the 46 PAC cases,42 (91.3%) cases showed positive for P504S,including 25 cases (54.3%) who showed strongly and diffusely positive (+++) for cytoplasmic staining.In 7 (87.5%) of the 8 HGPIN cases,the specimens were also positive for P504S,and only 1(2.9%)of the 35 BPH cases showed focally weakly positive (+) for P504S.All the 8 HGPIN cases (100%) and 33 (94.3%) of the 35 BPH cases showed positive for CK34?E12 and p63,while all the 46 PAC cases showed negative for CK34?E12 and p63.In 44 (95.7%) of the 46 PAC cases,the specimens were positive staining for PSA.Conclusions P504S has high sensitivity and good specificity in the diagnosis of PAC.P504S staining in combination with HE,CK34?E12,p63 and PSA staining can improve the accurate diagnosis of PAC.