| Grifola frondosa (maitake) was vigorously developed in recent years because of its unique flavor and effective health care. Commercial production began in Japan in 1970s, and now had achieved industrial and year-round production. In China, Qianxi of Hebei province and Qingyuan of Zhejiang province had been growing this kind of rare mushroom with very simple facilities seasonally. The key technologies of maitake's industrial cultivation mainly include strain screen, formulation optimization, bagging(bottling) and parameters controlling. Every process could be controlled precisely with standard operation procedure. Therefore, it is crucial to determine technologies and process parameters for industrial cultivation of Grifola frondosa.The excellent strain was screened for industrial cultivation. The production was compared between solid and liquid spawn. The correlation between the nitrogen content of the substrate and fruiting bodies was studied with the wheat bran and corn meal as nitrogen source in order to optimize the high-yield formula of the substrate. The bagging process and the time of after-ripening was also optimized. The mechanism of primordium formation and fuiting bodies development was also explored for theoretical foundation on industrial cultivation.The main results are as follows:1. The growth rate, mycelium rivalry and cultivated characters were detected among 11 strains. The results showed that the strain G11 was excellent for industrial cultivation with moderate growth rate,73 days of crop circle time, excellent quality of fruiting bodies identified as 3.3 and 35.7% biological efficiency.2. Response surface analysis was employed to optimize fermentation medium composition for the liquid spawn with the mycelium biomass as the index. A Plackett-Burman design was applied to evaluate the effects of different components in the medium. The results showed that wheat bran and corn powder were found to be the major factors to the biomass. The steepest ascent method was used to access the optimal region of the medium composition. The concentrations of the two factors were optimized subsequently using central composite design and response surface methodology. The results showed that the optimal medium composition was patato 225g, glucose 25g, wheat bran 38.48g/L, corn powder 48.92g/L, peptone 6.5g, beef extract 5.5g, potassium dihydrogen phosphate 1.25g, magnesium sulfate 3.5g and water 1000mL, respectively. Liquid spawn demonstrated superior to solid ones as the seed for cultivation with shorter corp circle time and better quality of fruiting bodies.3. The nitrogen content of the substrate had great effects on the corp circle time, biological efficiency (BE) and quality of fruiting bodies. The crop circle time was longer or couldn't form fruiting bodies with the percentage of nitrogen source increased. The BE was increased until] a certain point. The optimized high yield formulation was composed as wood sawdust 34.5%, cotton seed hulls 34.5%, wheat bran 7.5%. corn meal 22.5%, gypsum 1% with 64%-65% moisture content. The BE reached 43.1% with this formulation whose nitrogen content was 1.1272%. and the nitrogen content of fruiting bodies also reached peak,5.1528%, or the protein content up to 32.205%.4. The bagging tightness had a great impact on the development of Grifola frondosa, and the BE appropriately increased with the tightness improved. The weight of substrat had no significant impact on BE, and the development of fruiting bodies would be obstructed when the weight was up to higher value. The results showed that the weight of substrat 850g,12-13cm high with the bag of 17mm×33mm×0.05mm was the best bagging process.5. Fully after-ripening was necessary for the development of Grifola frondosa. The time of primordial formation and fruiting body development of ripening 20 days,30 days and 40 days was shorter than 0 and 10 days. The best after-ripening time was 20 days when the effective temperature reached 950℃with 77 day crop circle time,43.7% BE and 3.9 quality of fruiting bodies.6. Three stages included mycelium recovery, budding and intergrow budding were defined in primordia formation period, and four stages included brain, post-brain, cauliflower and mature were defined in fruiting body development period. The requirement of environmental control such as temperature, relative humidity, CO2 and light could be quite different in each stage. Scanning electron microscopy indicated that mycelium gatherrounded into the middle of the collection. and continued to twist together after scratching. The surface of the mycelium is rough. The cap-like structure were differentiated by the front of the hyphae and pipeline-like structure were also observed in latter stage. |
PDF Full Text Request