The Application Of Rape Straw In The Submerged Culture Of Pleurotus Eryngii

The effects of exterior factors on the ligninolytic and cellulose enzyme anddry weight of mycelium of Pleurotus eryngii in rape straw matrix under thesubmerged culture were studied. The objects of this work were to explore thepossibility that rape straw was utilized as substitute carbon resource and realize thesave the cost of production and make the use of the straw: the organic solid wastesof agriculture sufficiently and reasonably; explore the effects of the addition ofexterior factors on the ligninolytic and cellulose enzyme and the relationshipbetween the activities of ligninolytic and cellulose enzyme and myceliumproduction; and provides the reference for the production of ligninolytic andcellulose enzyme of P. eryngii in straw medium under the liquid fermentation andimproving the enzyme production ability by means of optimization of cultureconditions. Exterior factors include different nitrogen sources:1%peptone, beandreg powder, ammonium nitrate, ammonium sulfate, tartaric acid ammonium;metal ions:0.5mM FeSO4, KCl, CaSO4, CuSO₄, MnSO4, ZnSO4; organic acid:1,3and5mM oxalate and glycolic acid; different concentration of Tween80. Theresearch results were presented as following:The study on the ligninolytic enzyme:The result showed that compared to the control,1%peptone and bean dregpowder increased significantly the activities of manganese peroxidase （MnP） andthe activities of MnP were1833.3U/L and1353.3U/L on5thand7thday respectively.1%peptone and bean dreg powder also increased significantly the activities oflaccase （Lac）, and the activities of Lac were2584.4U/L and2162.7U/L on7thdayrespectively. Of6different metal ions,0.5mM Cu²⁺increased MnP and Lacremarkably compared to the control, and they both reached their peak activities on7thday, which were1543.4U/L and1623.2U/L respectively. But Fe²⁺decreasedsignificantly the activities of MnP and Lac. Mn²⁺made no difference compared to the control.1mM glycolic acid and oxalate increased significantly the activities ofMnP and Lac respectively, the peak activities of MnP and Lac were1562.3U/L and2012.4U/L on7thday respectively. Of different concentration of Tween80,0.1%increased MnP remarkably compared to the control, which reached1832.4U/L,which was678.8U/L higher than the control.0.1%Tween80increased Lacremarkably too. The peak activity was1441.1U/L on5thday.The study on the cellulose enzyme:The result showed that1%peptone and bean dreg powder increasedsignificantly the activities of the filter paper enzyme compared to the control, andthe activities of the filter paper enzyme were1004.0U/L and1051.8U/L on5thdayrespectively,1%ammonium sulfate increased significantly the activity of the Cxenzyme, the peak activity was2441.3U/L, which was2.6times the control. Of sixdifferent metal ions,0.5mM Ca2+and Zn²⁺increased the filter paper enzymeremarkably compared to the control, but Cu²⁺and Fe²⁺decreased the activities ofthe filter paper enzyme and Cx enzyme.0.5mM Mn²⁺increased the activity of Cxenzyme most significantly, its activity was2661.3U/L, was2.3times the control;3mM oxalate and1mM glycolic acid increased significantly the activities of thefilter enzyme, which reached1379.6U/L and1403.9U/L respectively, which were662.6U/L and686.9U/L higher than the control;5mM oxalate and1mM glycolicacid increased significantly the activities of Cx enzyme, which reached3298.7U/Land3673.5U/L. But5mM oxalate and5mM glycolic acid decreased significantlythe activities of filter paper enzyme and Cx enzyme respectively. Of differentconcentration of Tween80,0.075%and0.1%increased filter paper enzymeremarkably compared to the control, which reached1308.6U/L and1450.3U/L, but0.15%restrained its activities significantly;0.1%and0.125%Tween80increasedCx remarkably, which reached3196.4U/L and3058.3U/L respectively.The study on the dry weight of P. eryngii mycelium:The result showed that compared with other nitrogen sources, the highest dryweight of mycelium was obtained when the nitrogen source was bean dreg powder,the dry weight of P. eryngii mycelium was0.53g/100mL. However the superiorityof the production of P. eryngii mycelium was not obvious when1%bean dreg powder as nitrogen source, so different concentration of bean dreg powder wereadded into the nitrogen source base medium to explore the most suitableconcentration for the growth of P. eryngii. The highest dry weight was obtainedwhen the concentration was2%, the dry weight was1.50g/100mL. Of6differentmetal ions, compared to the control,0.5mM Mn²⁺, Cu²⁺, Zn²⁺all increased the dryweight of mycelium remarkably, which reached1.47g/100mL,1.45g/100mL,1.30g/100mL respectively.1mM glycolic acid and1mM oxalate increasedsignificantly the dry weight of mycelium respectively, the dry weight of P. eryngiimycelium were1.48g/100mL and1.43g/100mL respectively. Of differentconcentration of Tween80,0.1%increased the weight of mycelium remarkablycompared to the control, which reached1.40g/100mL. Through the comparion ofthe relation between the activity of the ligninolytic enzyme and the celluloseenzyme and the production of the mycelium of P. eryngii, we can conclude thatthere is a certain relationship between the activity of ligninolytic enzyme and thecellulose enzyme and the production of the mycelium of P. eryngii.According to the above experiment conclusions, the carbon source （rapestraw）, the optimum nitrogen source, the metal ions and the organic acid were usedas the design elements of orthogonal experiment. Orthogonal experiment resultsshowed that, the optimum medium for the production of P. eryngii mycelium wascomposed by3%rape straw,2%bean dreg powder,0.25mM CuSO₄,0.25mMMnSO4,0.5mM oxalate and0.5mM glycolic acid. The dry weight of P. eryngiimycelium was2.03g/100mL when rape straw was substituted by glucose; when P.eryngii was cultured in the optimum medium, the dry weight of mycelium was1.66g/100mL, which was81.77%to the control （glucose as the carbon source）. Sorape straw can be used as the substitute carbon source in the submerged culture of P.eryngii.