Search

Feather biodegradation is an important premise for efficient resource development and utilization, in which keratinase plays an important role. However, there are few keratinases that combine the high activity, thermal stability, and organic solvent tolerance required for industrialization. This paper reported an efficient feather-degrading Pseudomonas aeruginosa 4-3 isolated from slaughterhouses. After 48 h of fermentation by P. aeruginosa 4-3 in a feather medium at 40 °C, pH 8.0, keratinase was efficiently produced (295.28 ± 5.42 U/mL) with complete feather degradation (95.3 ± 1.5%). Moreover, the keratinase from P. aeruginosa 4-3 showed high optimal temperature (55 °C), good thermal stability, wide pH tolerance, and excellent organic solvent resistance. In addition, P. aeruginosa 4-3-derived aminopeptidases also exhibit excellent thermal stability and organic solvent tolerance. Encouragingly, the reaction of crude keratinase and aminopeptidase with feathers for 8 h resulted in a 78% degradation rate of feathers. These properties make P. aeruginosa 4-3 keratinase and aminopeptidase ideal proteases for potential applications in keratin degradation, as well as provide ideas for the synergistic degradation of keratin by multiple enzymes.

A gradient reversed-phase high-performance liquid chromatography (HPLC) method was developed for the separation and determination of free ergosterol in ganoderma spore lipid (GSL) extracted from the sporoderm-broken germinating spores of Ganoderma lucidum. Sodium hydroxide in methanol was added for the hydrolysis of ergosteryl esters to determine the total content of ergosterol in GSL by HPLC. A 0.04 M concentration of sodium hydroxide in reaction mixtures was appropriate for the complete hydrolysis of ergosteryl esters without a significant loss of ergosterol during saponification. In addition, the ergosterol content in four commercial GSL softgel supplements from four different firms was determined. The results showed that the ergosterol content in these samples had significant differences. Ergosterol content may be a suitable marker for evaluating the quality of GSL products.

Streptokinase (SK) is a specific effective medicine for thrombolytic therapy of acute myocardial infarction. This study established a process for the pilot production of recombinant streptokinase (r-SK). Engineering bacteria were fermented in a 20-l fermentor to produce r-SK. After simple renaturation and purification, 12.9 g of r-SK with 97.8% of purity and about 10 5 IU mg −1 of specific activity was obtained, the yield of protein and the recovery of activity were 44.9% and 51%, respectively. Finally, the r-SK was made into about 700 doses of injections for clinical applications.

High cell density fermentation production of recombinant human growth hormone was studied in Escherichia coli. The results showed that by using glycerol instead of glucose as carbon source and feeding in a specific fed-batch mode, by controlling the stirrer speed and keeping the dissolved oxygen level at 20–25% saturation, cell density increases from 38.6 to 118.8 g/l, the production of r-hGH remained high and the fermentation time was reduced from 16 to 10 h.

A cDNA fragment coding human interleukin-6 (IL-6) was inserted into the vector pSXIVVI + X3 with the control of Syn and XIV promoters. The Sf9 cells ( Spodoptera frugiperda ) were co-transfected with the recombinant plasmid and TnNPV DNA ( Trichoplusia ni nuclear polyhedrosis virus DNA). Cells infected with recombinant virus synthesized IL-6 protein at a level of approx. 42% of total cellular protein. IL-6 activity in infected cells was measured by using the IL-6-dependent mouse B hybridoma cell line 7TD1 and MTT colorimetric assay, the highest expression level, 2.82 × 10 6 u/ml, was obtained at 96 h after infection. Western blot analysis of infected larvae protein extracts showed that the virus-mediated IL-6, with a molecular weight of ∼21 kDa, shared antigenic sites with the authentic counterpart. However, no evidence of its bioactivity was found, IL-6 activity was determined only for IL-6 expressed by insect cells.

The ratios of stable carbon isotopes ((13)C/(12)C) of ganoderma fruiting body, ganoderma spore, ganoderma spore lipid (GSL) and individual fatty acids in GSL were determined by gas chromatography-stable isotope ratio mass spectrometry and elemental analysis-stable isotope ratio mass spectrometry. These values fall into a range from -26.9 to -23.3 per thousand, suggesting that the cut log as the Ganoderma-cultivated substrate in Fujian, China, may belong to C3 plants. Eighteen fatty acids were identified and their abundances measured by gas chromatography-mass spectrometry in the six GSL samples with C(16:0), C(18:0), C(18:1) and C(18:2) as major constituents, and C(16:1) is evidently enriched compared with the other edible vegetable oils. On the basis of the compositions of fatty acids and stable carbon isotopes in GSL, we have developed a novel method to detect the adulteration of GSL products with cheaper edible vegetable oils. An example of ideal blending between GSL and C4 or C3 vegetable oil is further provided to expound the discrimination procedures and corresponding sensitive indicators. Simultaneously, the carbon isotope fractionation in the biosynthesis of individual fatty acids was observed, revealing that the formation of C(18:0) from C(16:0) in ganodema spores had no conspicuous (13)C enrichment of +0.4 per thousand for Ganoderma sinensis spore and +0.1 per thousand for G. lucidum spore; the desaturation of C(18:0) to C(18:1) resulted in a distinct (13)C depletion of -1.4 per thousand for G. sinensis spore and -0.9 per thousand for G. lucidum spore; and the next desaturation from C(18:1) to C(18:2) displayed no evident (13)C fractionation of -0.1 per thousand for G. sinensis spore and -0.2 per thousand for G. lucidum spore.