| As one of the earliest recognized and cultivated edible fungi in China,Lentinula edodes has a history of artificial cultivation for more than 800 years.In recent years,with the acceleration of intensive production of Lentinula edodes,the contradiction between the demand for transformation and upgrading of Lentinula edodes industry and the traditional seed production mode of Lentinula edodes has become increasingly prominent.The traditional solid strain mode has the problems of high cost,long seed production cycle and low production efficiency,which is one of the main technical bottlenecks restricting the transformation of Lentinula edodes production mode.Different from the production mode of solid spawn,liquid spawn are produced by promoting the rapid growth and reproduction of edible fungi mycelium through liquid fermentation.They have the advantages of short production cycle,convenient inoculation,rapid mycelial growth,large number of germination points and high yield.At present,liquid strains have been successfully applied to edible fungi,such as flammulina velutida,Pleurotus eryngii and Auricularia auriculata.At present,the research on liquid spawn of Lentinula edodes mainly focuses on the optimization of culture medium formula and fermentation conditions.There is less research on the application of liquid strains in Lentinula edodes production.At present,few enterprises apply liquid spawn to stabilize and large-scale production of Lentinula edodes.In this paper,the effects of 9 carbon sources and 10 nitrogen sources on the mycelial growth rate of Lentinula edodes strains "Huxiang F2" and "Shenxiang 215" were studied.Further,the effects of 9 carbon sources and 10 nitrogen sources on mycelial biomass,fermentation solid volume ratio and extracellular enzyme activity of Lentinula edodes in liquid culture were studied.Finally,the bag planting experiment of Lentinula edodes liquid seed was carried out.The main results are as follows:1.Optimization of Lentinula edodes mother culture medium.In the carbon source experiment,PDA was used as the basic formula,and the mycelial growth rate was used as the index to select the best carbon source through single factor;In the nitrogen source experiment,the carbon source was fixed as molasses,and the mycelial growth rate was taken as the index.The optimum nitrogen source was selected through single factor experiment.The results showed that carbon source significantly affected the mycelial growth rate,and molasses significantly increased the mycelial growth rate of "Huxiang F2" and "Shenxiang 215",which were 6.10 mm/d and 5.32 mm/d respectively.The mycelial growth rate of "Huxiang F2" was significantly lower than that of other carbon sources,which was 4.89 mm/d;Xylose was the carbon source,and the mycelial growth rate of " Shenxiang 215" was significantly lower than that of other carbon sources,which was 4.27 mm/d.Nitrogen source significantly affected the mycelial growth rate,and yeast extract significantly increased the mycelial growth rate of "Huxiang F2",which was 4.01 mm/d;Soybean meal significantly increased the mycelial growth rate of "Shenxiang 215",which was 4.04 mm/d.The mycelial growth rate of "Huxiang F2" and "Shenxiang 215" was significantly lower than that of other nitrogen sources,which were 3.19 mm/d and 3.52 mm/d respectively.To sum up,molasses in the carbon source is conducive to the mycelial growth of Lentinula edodes,while glucose and xylose are used as carbon sources,the mycelial growth rate is slow.In the nitrogen source,yeast extract and soybean powder are conducive to mycelial growth,while urea is the nitrogen source,and the mycelial growth rate is slow.2.Optimization of Lentinula edodes liquid medium."Huxiang F2" strain was selected,and the fermentation parameters were set as temperature 25 ℃,rotating speed150 r/min and bottling volume 100 m L/ 250 m L～150 m L/ 250 m L.Through the two indexes of mycelial biomass and fermentation solid volume ratio,the suitable carbon and nitrogen source and addition amount and the suitable addition amount of inorganic salt were screened.The results showed that the carbon source significantly affected the mycelial biomass and fermentation solid volume ratio.The best comprehensive performance was molasses,the mycelial biomass was 8.04 g/L,the fermentation solid volume ratio was 98.69 %,and the relatively poor comprehensive performance was glucose,the mycelial biomass was only 5.89 g/L,and the fermentation solid volume ratio was 94.40 %.The nitrogen source significantly affected the mycelial biomass and the volume ratio of fermentation solids.The best comprehensive performance was bran,the mycelial biomass could reach 8.13 g/L,the volume ratio of fermentation solids could reach 98.86 %,and the poor performance was urea,the mycelial biomass was only 1.49 g/L,and the volume ratio of fermentation solids was 54.48 %.Through screening,the best carbon source is molasses,and the optimum addition amount is 15 ～20 g/L;The nitrogen source is wheat bran 10 g/L,the addition amount of magnesium sulfate is 0.5 ～ 1.0 g/L,and potassium dihydrogen phosphate is 1.5 g/L.3.Under different carbon and nitrogen sources,the activities of four extracellular enzymes(laccase,manganese peroxidase,lignin peroxidase and cellulase)of liquid spawn with different carbon and nitrogen sources during the inoculation period were detected.At the same time,the growth rate of mycelium in sawdust culture material and the activities of four extracellular enzymes(laccase,manganese peroxidase,lignin peroxidase and cellulase)in culture material after inoculation were detected.The results showed that the growth rate of mycelium on sawdust was significantly positively correlated with the cellulase activity of liquid spawn,and the correlation coefficient was0.263.At the initial stage of inoculating sawdust,the mycelial growth rate was significantly positively correlated with lignin peroxidase activity and cellulase activity,and the correlation coefficients were 0.309 and 0.471 respectively.Cellulase has high activity in liquid bacteria and in the early stage of inoculation with sawdust,which may be the key enzyme system for the growth of mycelium in sawdust,which needs to be further studied and proved.4.Optimization of fermentation conditions of Lentinula edodes liquid strain.Based on the optimized liquid medium(molasses 15～20 g/L,bran 10 g/L,potassium dihydrogen phosphate 1.5 g/L,magnesium sulfate 1.0 g/L),the single factor experiment was carried out on the basic fermentation conditions,and the fermentation model of liquid spawn of Lentinula edodes was established.The results showed that the optimum culture temperature was 25 ～ 26 ℃,and the optimum bottling volume was 100 m L/ 250 m L ～ 150 m L/250 m L;The optimum rotational speed of shaking table is 110 ～ 130r/min;The optimum initial p H is 5.0 ～ 6.0.5.Study on the application and cultivation of liquid formula with different carbon and nitrogen sources.The performance of cultivation bags inoculated with liquid seed formula of different carbon and nitrogen sources is different.The best performance of cultivation bags inoculated with liquid seed of 9 carbon sources is molasses,with the maximum total yield of 468.32 g/stick,and the poor performance is xylose,with the total yield of only 377.56 g/stick.After inoculation with 10 nitrogen source liquid seeds,the best performance of the cultivation bag is bran,and the total yield can reach 501.01g/ stick,while the poor performance is ammonium chloride,and the total yield is only408.41 g/ stick.6.To explore the inoculation technology of liquid spawn.To explore the effects of different inoculation date,inoculation amount and inoculation depth on the full bag time,the number of buds and yield of shiitake mushroom.Different inoculation dates affect the full bag time,the number of buds and yield of the first and second tides,as well as the total yield.The best inoculation date is on the 4th and 5th day of liquid culture.Different inoculation amounts affect the yield of the first tide,but have no effect on the full bag time and the number of buds of one or two tide mushrooms.Combined with production practice,the best inoculation amount is 5 m L/hole.The optimum inoculation depth was 9 cm. |
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