Search

Incubation with different concentrations of different carbon, nitrogen and metal ion sources was found to significantly influence Shiraia sp. SUPER-H168 laccase production. Based on the magnitude of the range, the factors were ranked as follows: starch > Cu2+ > yeast powder for laccase production. The optimal combination of factors was 20 g/L starch, 4 g/L yeast powder and 0.6 mM Cu2+. Other fermentation media and conditions were also studied. The maximal laccase yield of Shiraia sp. SUPER-H168 varied from 5,058 to 1.105 × 105 U/L. Shiraia sp. SUPER-H168 laccase DNA and its corresponding full-length cDNA were cloned and characterized; furthermore, the Shiraia laccase gene sequence is reported for the first time. The coding region of Shiraia sp. SUPER-H168 laccase consisted of a 1,848 bp open reading frame encoding a protein of 615 aa with a 21 aa signal peptide sequence. Three introns of 50, 49 and 51 bp in length were located at upstream of the N terminus. The molecular mass (66.7 kDa) and isoelectric point (7.63) were predicted. Additionally, the protein contained six potential N-glycosylation sites (Asn-X-Ser/Thr) and four conserved copper-binding domains. The neighbor joining phylogenetic tree demonstrated that Shiraia sp. SUPER-H168 laccase is an ascomycetes laccase closely related to Phoma sp. UHH 5-1-03 laccase.

Three extracellular polysaccharides (SP-1, SP-2 and SP-3) from Shiraia sp. Super-H168 under submerged fermentation were purified by using ethanol precipitation, chromatography separation on the DEAE-cellulose-32 column and the Sephadex G100 column. The molecular weights of SP-1, SP-2 and SP-3 were determined to be approximately 189 kDa, 130 kDa and 52 kDa, respectively. Monosaccharide analysis revealed that SP-1 was composed of mannose and glucose in molar ratios of 1:28.47, and SP-2 and SP-3 were both composed of mannose, glucose and galactose in molar ratios of 63.32:70.06:1 and 2.31:14.69:1, respectively. Three polysaccharides had very weak scavenging activity of superoxide radical (

Hypocrellin A production by Shiraia sp. SUPER-H168 was studied under solid-state fermentation. Corn was found to be the best substrate after evaluating eight kinds of agro-industrial crops and residues. The optimized solid-state fermentation conditions were as follows: inoculum size 3 x 10(6) spores, substrate particle size 0.8-1 mm, initial moisture content 50%, and temperature 30 degrees C. Six kinds of external carbon source and seven kinds of external nitrogen source were evaluated, respectively, for HA production. Glucose and NaNO(3) were the best. The combination of them was optimized by the response surface method. The optimum compositions of the supplementary glucose and NaNO(3) were 1.65 g/100 g and 0.43 g/L, respectively. Hypocrellin A production reached 4.7 mg/g.

Hypocrellins are important photodynamic therapy compounds for cancer disease. The effect of surfactants on hypocrellin production of Shiraia sp. SUPER-H168 was evaluated under submerged fermentation condition. The production of hypocrellins could reach 780.6 mg/l with the addition of Triton X-100, confirmed by color reaction, high performance liquid chromatography, electrospray ionization mass spectrometry and nuclear magnetic resonance experiments. According to our observation, treatment of the culture at the beginning of the fermentation was most effective, and the yield of hypocrellins was much lower with the addition of Triton X-100 during the log phase and stationary phase. Shiraia sp. SUPER-H168 could not produce hypocrellin with the addition of other tested surfactants, such as Tween 40, Triton X-114 and SDS. The experimental results indicated that Shiraia sp. SUPER-H168 could not produce hypocrellins without Triton X-100 under submerged fermentation condition.