Supplemented of Agricultural Wastes Improve the Sawdust Degradation Efficiency by Pleurotus pulmonarius

• Main Authors: LIU, MEI-LAN, 劉美蘭
• Other Authors: FANG, HSIN-YU
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/rr5yr8

碩士 === 中華醫事科技大學 === 醫學檢驗生物技術系碩士班 === 107 === Sawdust was used as basic material for mushrooms cultivation. Considerd of the environmental protection, the mass of sawdust decreased in recent years. We known that sawdust and agriculture wastes both were constituted by lingocellulose. Proposed the sawdust can be replaced by agriculture wastes, it did not merely reduce the demand of sawdust, but also reduce the environmental pollution caused by their accmulatuon. In this work, we evaluate the feasibility that agricultural waste used to replace sawdust in mushrooms cultivation. Lignocellulose was composed of lignin, hemicellulose and cellulose. The main lignocellulolytic enzymes were laccase, xylanase and CMCase (carboxymethyl cellulase). The strain of mushroom with higher lignocellulolytic enzymes activity could grow faster in media contained lignocellulose, thus the lignocellulolytic enzymes activity could serve as the indicator for strain screening. Six strains of mushrooms, included Pleurotus Pulmonarius, Pleurotus eryngii, Pleurotus citrinopileatus, Auricularia Polytricha, Hericium erinaceus, and Lentinula Edodes, were separately isolated from our lab. To evalulate their lignocellulolytic enzymes activity, strains were incubated in a liquid medium containing 1% sawdust for 9 days and the activity of laccase, xylanase and CMCase were assayed separately. Results demonstrated the Pleurotus Pulmonarius show a higher lignocellulolytic activity with a laccase activity of 2.55±0.23 U, a xylanase activity of 1.23±0.12 U, and an CMCase activity of 0.18±0.11 U. Time course study of lignocellulolytic enzymes secreted by Pleurotus Pulmonarius was further surveyed. Results shown the highest activity of laccase (3.04±0.21 U) was observed on day 3; the highest activity of xylanase (1.79±0.10 U) was observed on day 5 and the highest activity of CMCase (0.12±0.01 U) was observed on day 9. These results demonstrated the degradation of sawdust was initiated from lignin, and then hemicellulose, and finally cellulose degradation. To assess the utility efficiency of different agricultural wastes by Pleurotus pulmonarius was performed in different 1% agricultural waste containing broth respectively and enzyme collected in different time period based on above results. Data shown the highest laccase activity was found in sugarcane bagasse media (8.54 ± 0.16 U), and then in corn husk media (7.03 ±1.19 U). The highest xylanase activity (13.14 ±.031 U) and CMCase activity (0.49 ±0.03 U) were both found in corn husk media. This indicated corn husk might sevred as substitute substrate for sawdust in Pleurotus pulmonarius culitivation. Lignocellulolytic enzymes from white-rot fungi were known belong to inducible enzymes. Their specificity and isoform may be changed depend on its substrate. To verify the difference lignocellulolytic enzymes production from different agricultural wastes media, zymogram were performed. In the laccase zymogram, two identical laccase isoforms were observed while cultivated in different agricultural wastes, and their molecular weights were 56.23 kDa and 40.73 kDa respectively. In the xylanase and CMCase zymogram, enzymes from different agricultural wastes media displayed the similar zymogram profiles that the observed band smeared from 180-70 kDa. The results indicated lignocellulolytic enzymes produced from other agricultural wastes had the correspond zymogram band to the lignocellulolytic enzymes produced from sawdust. Furthermore, we also found crude enzyme solution produced from different agricultural wastes could enhance the sawdust degradation. The crude enzyme solution produced from corn husk was evidenced that exhibited the best hydrolysis efficiency on 1% sawdust and released the total reducing sugar content of 1036.00±129.64 mg. Based on the above results, addition of corn husk should induce more lignocellulolytic enzymes production and then improve the efficiency of sawdust decomposition. To explore the substitute extent of corn husk, Pleurotus pulmonarius incubate in different combination ratio of sawdust and corn husk were carried out. Results showed that 60% sawdust + 40% corn husk with Pleurotus pulmonarius had better laccase activity (4.32±0.26 U), xylanase activity (2.69±0.05 U) and CMCase activity (0.48±0.02 U), and the extent of decomposition reached 50.77±0.75%.