ABSTRACT
Cordycepin,which has great immunomodulatory activities such as anticancer,antifungal,antivirus,antileukemia and lipid-lowering ones,is the secondary metabolite of Cordyceps militaris (C.militaris).Liquid submerged fermentation is the common cultivation process to produce cordycepin.To optimize the fermentation process and improve production,monitoring the cordycepin secretion in the fermen-tation is essential.The measurement based on chromatography-mass spectrometry methods is generally involved in the complex sample pretreatments and time-consuming separation,so more rapid and convenient methods are required.Matrix-assisted laser desorption ionization mass spectrometry(MALDI-MS) is more attractive for faster and direct detection.Therefore,MALDI-MS detection combined with isotope-labeled internal standard was applied to the measurement of cordycepin content in the fermentation broth and mycelium.This method made accurate quantification of cordycepin in the range of 5-400 μg/mL with a relative standard deviation of 5.6％.The recovery rates of fermentation samples after the 1,13,and 25 days were 90.15％,94.27％,and 95.06％,respectively.The contents of cordycepin in the mycelium and fermentation broth were 136 mg/g and 148.39 mg/mL on the 20th culture day,respectively.The cordycepin secretion curve of the liquid fermentation of C.militaris was real-time traced over 25 days.
ABSTRACT
Abstract Large quantities of kitchen waste are produced in modern society and its disposal poses serious environmental and social problems. The aim of this study was to isolate degradative strains from kitchen waste and to develop a novel and effective microbial agent. One hundred and four strains were isolated from kitchen waste and the 84 dominant strains were used to inoculate protein-, starch-, fat- and cellulose-containing media for detecting their degradability. Twelve dominant strains of various species with high degradability (eight bacteria, one actinomycetes and three fungi) were selected to develop a compound microbial agent "YH" and five strains of these species including H7 (Brevibacterium epidermidis), A3 (Paenibacillus polymyxa), E3 (Aspergillus japonicus), F9 (Aspergillus versicolor) and A5 (Penicillium digitatum), were new for kitchen waste degradation. YH was compared with three commercial microbial agents-"Tiangeng" (TG), "Yilezai" (YLZ) and Effective Microorganisms (EM), by their effects on reduction, maturity and deodorization. The results showed that YH exerted the greatest efficacy on mass loss which decreased about 65.87% after 14 days. The agent inhibited NH3 and H2S emissions significantly during composting process. The concentration of NH3 decreased from 7.1 to 3.2 ppm and that of H2S reduced from 0.7 to 0.2 ppm. Moreover, E4/E6 (Extinction value460nm/Extinction value665nm) of YH decreased from 2.51 to 1.31, which meant YH had an obvious maturity effect. These results highlighted the potential application of YH in composting kitchen waste.