Astaxanthin is a useful pigmentation source in fish aquaculture. It has strong antioxidative activity and therefore has potential application in delaying aging and degenerative diseases in human and animals. In recent years, there is a growing demand for astaxanthin. The red yeast Xanthophyllomyces dendrorhous (called Phaffia rhodozyma before) is one of the most promising microorganisms for the commercial production of astaxanthin. During fermentation, X. dendrorhous shows the Crabtree effect. Higher glucose concentration will cause significant reductions in biomass and astaxanthin production. Therefore, fed-batch processes are particularly useful. In this paper, effects of glucose-feeding strategies on astaxanthin production by X. dendrorhous were studied. Based on the substrate inhibition model, an optimized two-stage feeding strategy for astaxanthin production of high-cell-density fermentation was proposed. Glucose concentration was first controlled at about 25 g/L during the lag phase and the early exponential phase. In such case, biomass could reach its maximum value in relatively short time. Then the glucose concentration was controlled at about 5 g/L in the later exponential phase and stationary phase. The synthesis of astaxanthin could be effectively prolonged. The results showed that the optimized two-stage feeding strategy was the best among all the feeding strategies, and could obtain the highest biomass (23.8 g/L) and astaxanthin production (29.05 mg/L), which was a significant increase (52.8% and 109% respectively) compared with a batch process.
Basidiomycota ; metabolism ; Fermentation ; Kinetics ; Models, Biological ; Xanthophylls ; biosynthesis

In order to explore the antitumor effect and mechanism of different extracts of cultivated Phellinus vaninii fruit body on H₂₂ tumor bearing mice, 150 ICR mice were randomly divided into blank group, model group, CTX group, P. vaninii water extract group, ethanol extract group, petroleum ether extract group and crude polysaccharide group. H₂₂ liver cancer cells were used to establish a solid tumor model and the mice were sacrificed on the 10th day after administration. The spleen and thymus organ index and tumor inhibition rate were calculated, the serum levels of TNF-α, INF-γ, VEGF, and hematoxylin-eosin were detected, and the immunohistochemical staining method was used to observe the pathological changes of tumor tissues, while Western blotting was used to detect the expression of tumor-related proteins. The high-dose petroleum ether extract group showed the best tumor inhibition rate (73.21%), increased serum levels of TNF-α, IFN-γ, and VEGF, as well as significantly promoted tumor necrosis and ablation. The immunohistochemistry of the water extract group showed negative regulation, indicating an insignificant tumor suppression. Western blotting showed the apoptosis genes Caspase-3, Caspase-9 and pathway genes NF-κB and JAK were all highly expressed in each administration group compared with the model group, and their expression levels gradually decreased with increasing doses. In summary, the petroleum ether extract of P. vaninii fruit body showed a significant anti-tumor effect which is presumably mediated through the mitochondrial pathway. The metabolism of drug in the body induces activation of Caspase-3 and Caspase-9 apoptotic proteins by Bax, Bcl-2, and TNF, which further caused nuclear chromatin or DNA to condense or degrade, and subsequently destroy the normal proliferation of tumor cells, thereby inducing their apoptosis and inhibiting tumor growth.
Animals ; Apoptosis ; Basidiomycota ; Mice ; Mice, Inbred ICR ; Neoplasms/metabolism*

OBJECTIVETo investigate the submerged culture conditions and nutritional requirments for the production of mycelial biomass and exopolysaccharides (EPS) by medicinal mushroom Phellinus baumii.

METHODThe carbon sources, nitrogen sources, inoculum volume, initial pH and temperature were investigated based on shake flask cultures, respectively.

RESULTThe glucose was the most suitable carbon source for both mycelial biomass and EPS production, soy peptone was favorable nitrogen sources for both mycelial biomass and EPS production. The optimal inoculum volume, initial pH and temperature for both mycelial growth and EPS production were 6%, 6.0 and 28 degrees C, respectively.

CONCLUSIONThe study obtained basic datas for large-scale submerged culture of P. baumii.

Basidiomycota ; growth & development ; metabolism ; Biomass ; Hydrogen-Ion Concentration ; Mycelium ; growth & development ; metabolism ; Polysaccharides ; biosynthesis ; Temperature

To evaluate the effectiveness of enzymatic assisted extraction (EAE) of lipid from the oleaginous yeast Rhodosporidium toruloides in the presence of beta-1,3-glucomannanase at a larger scale, we investigated the effects of enzymatic treatment and extraction conditions on lipid extraction yields at 10-L scale by using the broth of R. toruloides Y4 as the feed and ethyl acetate as the solvent. When it was treated for 0.5 h, the lipid extraction yield reached 71.1%, indicating that the enzymatic treatment process reached similar efficiency to that obtained at 10-mL scale. The inhibitory effect of emulsification was greatly reduced by repeated extraction. After extracted for three times, yields of lipid extraction, solvent recovery and total material recovery reached 92.9%, 87.0% and 94.2% respectively. As it can use the lipid production slurry with good extraction efficiency, EAE technology is promising for industrial production of microbial lipids.
Basidiomycota ; metabolism ; Biofuels ; Bioreactors ; Fermentation ; Industrial Microbiology ; Lipids ; biosynthesis ; isolation & purification ; beta-Mannosidase ; metabolism

To shorten the cultivation time and reduce the consumption of raw materials for microbial lipid production, oleaginous yeast Rhodosporidium toruloides AS 2.1389 was cultivated using a two-stage culture mode, in which the cell propagation and lipid accumulation were separated. The yeast cells recovered from the propagation culture were re-suspended in glucose solution for lipid accumulation, through which lipid content over 55% of the dry cell weight was achieved, the longer the propagation stage was, the higher the lipid content. Analysis of the lipid indicated that the long-chain fatty acids with 16 and 18 carbon atoms were major components, suggesting that the lipid can be an alternative feedstock for biodiesel production.
Basidiomycota ; growth & development ; metabolism ; Biofuels ; Cell Culture Techniques ; methods ; Fermentation ; Industrial Microbiology ; methods ; Lipids ; biosynthesis

A derivative ratio spectrophotometric method was used for the simultaneous determination of beta-carotene and astaxanthin produced from Phaffia rhodozyma. Absorbencies of a series of the standard carotenoids in the range of 441 nm to 490 nm demonstrated that their absorptive spectra accorded with Beer's law and that the additivity when the concentrations of beta-carotene and astaxanthin and their mixture were within the range of 0 to 5 microg/ml, 0 to 6 microg/ml, and 0 to 6 microg/ml, respectively. When the wavelength interval (lambda) at 2 nm was selected to calculate the first derivative ratio spectra values, the first derivative amplitudes at 461 nm and 466 nm were suitable for quantitatively determining beta-carotene and astaxanthin, respectively. Effect of divisor on derivative ratio spectra could be neglected; any concentration used as divisor in range of 1.0 to 4.0 microg/ml is ideal for calculating the derivative ratio spectra values of the two carotenoids. Calibration graphs were established for beta-carotene within 0-6.0 microg/ml and for astaxanthin within 0-5.0 microg/ml with their corresponding regressive equations in: y=-0.0082x-0.0002 and y=0.0146x-0.0006, respectively. R-square values in excess of 0.999 indicated the good linearity of the calibration graphs. Sample recovery rates were found satisfactory (>99%) with relative standard deviations (RSD) of less than 5%. This method was successfully applied to simultaneous determination of beta-carotene and astaxanthin in the laboratory-prepared mixtures and the extract from the Phaffia rhodozyma culture.
Algorithms ; Basidiomycota ; metabolism ; Spectrophotometry, Ultraviolet ; methods ; Xanthophylls ; beta Carotene ; analogs & derivatives ; analysis ; chemistry

Phaffia rhodozyma is one of the organisms for production of astaxanthin, and the key process for extracting intracellular astaxanthin is cell disruption. In this work, cell disruption for extracting astaxanthin from Phaffia rhodozyma was studied with autoclave method at low acid concentration. The optimum disrupting conditions were: autoclave pressure 0.1 MPa, 121 degrees C; hydrochloric acid concentration 0.5 mol/L; liquid to material ratio (V/W) 30 mL/g dry cell weight and disruption time 2 min. Under the optimum conditions, medium scale experiment showed that astaxanthin and total carotenoids recovery from Phaffia rhodozyma were (84.8 +/- 3.2)% and (93.3 +/- 2)%, respectively. This new method can lead to no poisonous residues and get high extraction yield, which have good prospects to be put into industrial production.
Basidiomycota ; chemistry ; Carotenoids ; isolation & purification ; Cell Wall ; metabolism ; Hot Temperature ; Hydrochloric Acid ; Xanthophylls ; isolation & purification

A comparative study of batch and repeated batch process was carried out for astaxanthin fermentation of Phaffia rhodozyma to develop a more economical method for astaxanthin industrial production. In shaking flask fermentation, the change of biomass and astaxanthin production was studied to compare the five-day cycle with four-day cycle of repeated batch culture of P. rhodozyma. Astaxanthin production increased at first and then decreased subsequently in seven cycles, yet the yield of astaxanthin in the next six cycles remains higher than that of the first cycle. Comparing the average production of astaxanthin in the seven cycles, four-day cycle performed even better than five-day cycle. Subsequently, a repeated fed-batch process was used in a 5-1 bioreactor. The experimental data showed that biomass and astaxanthin production of the second batch could reach the level of the first batch, no matter that the carbon source was glucose or hydrolysis sugar of starch. This result showed that this strain had good stability, and thus repeated batch and fed-batch process could be applied in astaxanthin fermentation for economical purpose.
Basidiomycota ; genetics ; metabolism ; Batch Cell Culture Techniques ; methods ; Bioreactors ; microbiology ; Fermentation ; Industrial Microbiology ; methods ; Xanthophylls ; biosynthesis

β-carotene has a wide range of application in food, pharmaceutical and cosmetic industries. For microbial production of β-carotene in Saccharomyces cerevisiae, the supply of geranylgeranyl diphosphate (GGPP) was firstly increased in S. cerevisiae BY4742 to obtain strain BY4742-T2 through over-expressing truncated 3-hydroxy-3-methylglutaryl-CoA reductase (tHMGR), which is the major rate-limiting enzyme in the mevalonate (MVA) pathway, and GGPP synthase (GGPS), which is a key enzyme in the diterpenoid synthetic pathway. The β-carotene synthetic genes of Pantoea agglomerans and Xanthophyllomyces dendrorhous were further integrated into strain BY4742-T2 for comparing β-carotene production. Over-expression of tHMGR and GGPS genes led to 26.0-fold increase of β-carotene production. In addition, genes from X. dendrorhous was more efficient than those from P. agglomerans for β-carotene production in S. cerevisiae. Strain BW02 was obtained which produced 1.56 mg/g (dry cell weight) β-carotene, which could be used further for constructing cell factories for β-carotene production.
Basidiomycota ; enzymology ; Farnesyltranstransferase ; genetics ; metabolism ; Hydroxymethylglutaryl CoA Reductases ; genetics ; metabolism ; Metabolic Engineering ; Polyisoprenyl Phosphates ; Saccharomyces cerevisiae ; metabolism ; beta Carotene ; biosynthesis

Basidiomycete PM2, a lignin-degrading white rot fungus, produces lgnin peroxidase (Lip) and manganese peroxidase (Mnp) in nutrient nitrogen limited liquid cultures. This fungus was selected for its ability to decolorize azo group of dyes. In order to improve production of the peroxidases and rapid dye decolorizing activity by basidiomycete PM2, the addition of veratryl alcohol or Tween 80 to nutrient nitrogen limited liquid cultures were tested. It was found to have a large stimulatory effect on Mnp activities and decolorization rate of azo dyes. A maximum Mnp activities of 254.2 u/L with veratryl alcohol and 192.2 u/L with Tween 80 were achieved respectively. These values were about 3.4-fold and 2.5-fold higher than that obtained in the control cultures (without alcohol or Tween 80), whereas the levels of Lip activity detected were very low (about 12 u/L)in all the cultures. In further experiments using three kinds of azo dyes of congo red, orange G and orange IV, enzyme activities and dye decolorization were investigated in the above-mentioned cultures. The results showed that Mnp activities and decolorization were notably higher than those obtained in the control cultures in the presence of azo dyes. Cultures supplemented with Tween 80 were more adequate for dye decolorization. The rates of the decolorization with Tween 80 of congo red (95.4%), orange G (98.5%) and orange IV (54.4%) after 24 hours of dye incubation were higher than that supplemented with veratryl alcohol. According to the results, Mnp activities secreted by basidiomycete PM2 play an essential role in the process of dye decolorization. Tween 80 was the main factor affecting the decolorization. The analysis of structure of the three kinds of azo dyes indicats that the extent of decolorization is affected by the dye molecular structure. The types and quantity of the substituted groups on the aromatic ring of azo dyes have effect on the percentage of biological decolorization.
Azo Compounds ; metabolism ; Basidiomycota ; enzymology ; metabolism ; Benzyl Alcohols ; pharmacology ; Coloring Agents ; metabolism ; Oxygenases ; biosynthesis ; Peroxidases ; biosynthesis ; Polysorbates ; pharmacology