Effect of Moisture Content and Inoculum Size on Cell Wall Composition and Ethanol Yield from Switchgrass after Solid-State Pleurotus ostreatus Treatment

2018 ◽  
Vol 61 (6) ◽  
pp. 1997-2006 ◽  
Author(s):  
Mengxing Li ◽  
Stephen M. Marek ◽  
Jiaqi Peng ◽  
Zhongdong Liu ◽  
Mark R. Wilkins

Abstract. The white-rot fungus is capable of selectively degrading lignin over polymeric sugars. Solid-state cultivation and subsequent simultaneous saccharification and fermentation for ethanol production were performed. Effects of moisture content (MC) and fungus inoculum on biomass degradation, ligninolytic enzyme, and ethanol production were evaluated. First, fungal pretreatment was performed with varied MC and inoculum levels and sampled every 20 days. The highest xylose yield observed was 15.6% for samples with 75% MC and 5 mL inoculum at fungal pretreatment of 40 days. The highest lignin degradation of 52% and highest ethanol yield of 31% (based on the glucan present in the raw switchgrass) were achieved for 80-day fungal-treated samples with 75% MC and 5 mL inoculum. Keywords: KLywords. Bioenergy, Fungal pretreatment, Oyster mushroom, Perennial grass.

2006 ◽  
Vol 49 (5) ◽  
pp. 699-704 ◽  
Author(s):  
Giovana Kirst Tychanowicz ◽  
Daniela F. de Souza ◽  
Cristina G. M. Souza ◽  
Marina Kimiko Kadowaki ◽  
Rosane Marina Peralta

Pleurotus pulmonarius (Fr) Quélet, produced laccase as the main ligninolytic enzyme when cultivated on solid-state cultures using corn cob as substrate. The addition of copper greatly increased the production of enzyme. The addition of 25.0 mM CuSO4 increased the level of laccase from 270 to 1,420 U.L-1 and the fungus showed high resistance to copper under the conditions used in this work.


1999 ◽  
Vol 65 (5) ◽  
pp. 1864-1870 ◽  
Author(s):  
Martin Hofrichter ◽  
Tamara Vares ◽  
Mika Kalsi ◽  
Sari Galkin ◽  
Katrin Scheibner ◽  
...  

ABSTRACT The basidiomycetous fungus Nematoloma frowardiiproduced manganese peroxidase (MnP) as the predominant ligninolytic enzyme during solid-state fermentation (SSF) of wheat straw. The purified enzyme had a molecular mass of 50 kDa and an isoelectric point of 3.2. In addition to MnP, low levels of laccase and lignin peroxidase were detected. Synthetic 14C-ring-labelled lignin (14C-DHP) was efficiently degraded during SSF. Approximately 75% of the initial radioactivity was released as14CO2, while only 6% was associated with the residual straw material, including the well-developed fungal biomass. On the basis of this finding we concluded that at least partial extracellular mineralization of lignin may have occurred. This conclusion was supported by the fact that we detected high levels of organic acids in the fermented straw (the maximum concentrations in the water phases of the straw cultures were 45 mM malate, 3.5 mM fumarate, and 10 mM oxalate), which rendered MnP effective and therefore made partial direct mineralization of lignin possible. Experiments performed in a cell-free system, which simulated the conditions in the straw cultures, revealed that MnP in fact converted part of the14C-DHP to 14CO2 (which accounted for up to 8% of the initial radioactivity added) and14C-labelled water-soluble products (which accounted for 43% of the initial radioactivity) in the presence of natural levels of organic acids (30 mM malate, 5 mM fumarate).


2016 ◽  
Vol 3 (02) ◽  
Author(s):  
Cornelius Damar Hanung ◽  
Ronald Osmond ◽  
Hendro Risdianto ◽  
Sri Harjati Suhardi ◽  
Tjandra Setiadi

White rot fungi of Marasmius sp. is a fungus which produce laccase in high activity. Laccase is one of the ligninolityc enzymes that capable to degrade lignin. This ability can be used for the pretreatment of lignocellulosic materials in the bioethanol production. Laccase was produced in flask by batch process using Solid State Fermentation (SSF). The optimisation was conducted by statistically of full factorial design. The particle size, moisture content, and Cu concentration were investigated in this study. Rice straw was used as solid substrate and the glycerol was used as the carbon sources in modified Kirk medium. The results showed that particle size of rice straw did not affect significantly to the enzyme activity. The highest laccase activity of 4.45 IU/g dry weight was obtained at the moisture content of 61% and Cu concentration of 0.1 mM.Keywords: laccase, Marasmius sp., optimisation, rice straw, solid state fermentation ABSTRAKJamur pelapuk putih, Marasmius sp. merupakan jamur yang menghasilkan enzim lakase dengan aktivitas tinggi. Lakase merupakan enzim ligninolitik yang dapat mendegradasi lignin. Kemampuan ini dapat digunakan untuk proses pengolahan awal bahan lignoselulosa pada pembuatan bioetanol. Produksi lakase dilakukan dalam labu dengan modus batch menggunakan fermentasi kultur padat. Optimisasi produksi enzim lakase dengan metode fermentasi padat dilakukan dengan  rancangan percobaan faktorial penuh. Pengaruh ukuran partikel, kelembapan, dan konsentrasi Cu diuji dengan medium penyangga jerami dengan menambahkan gliserol dalam medium Kirk termodifikasi sebagai sumber karbon. Penelitian ini menunjukkan bahwa ukuran jerami tidak berpengaruh signifikan terhadap aktivitas enzim. Aktivitas enzim lakase maksimum terjadi pada saat kelembapan 61% dan konsentrasi Cu 0,1 mM dengan aktivitas enzim lakase/berat kering tertinggi mencapai 4,45 IU/g.Kata kunci: lakase, Marasmius sp., optimisasi, jerami, fermentasi kultur padat


BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3797-3807
Author(s):  
Magdah Ganash ◽  
Tarek M. Abdel Ghany ◽  
Mohamed A. Al Abboud ◽  
Mohamed M. Alawlaqi ◽  
Husam Qanash ◽  
...  

Lignocellulolytic white-rot fungi allow the bioconversion of agricultural wastes into value-added products that are used in a myriad of applications. The aim of this work was to use corn residues (Zea mays L.) to produce valuable products under solid-state fermentation (SSF) with Pleurotus ostreatus. White-rot fungus P. ostreatus was isolated from maize silage (MS) and thereafter it was inoculated on MS as substrate and compared with maize stover (MSt) and maize cobs (MC) to determine the best lignocellulosic substrate for the production of lignocellulolytic enzymes and extracellular protein. The MS gave the highest productivity of CMCase (368.2 U/mL), FPase (170.5 U/mL), laccase (11.4 U/mL), and MnPase (6.6 U/mL). This is compared to productivity on MSt of 222 U/mL, 50.2 U/mL, 4.55 U/mL, and 2.57 U/mL, respectively; and productivity on MC at the same incubation period as 150.5 U/mL, 48.2 U/mL, 3.58 U/mL, and 2.5 U/mL, respectively. The levels of enzyme production declined with increasing incubation period after 15 and 20 days using MS and MC, respectively, as substrates. Maximum liberated extracellular protein content (754 to 878 µg/mL) was recorded using MS, while a low amount (343 to 408 µg/mL) was liberated with using MSt and MC.


2020 ◽  
Vol 8 (1) ◽  
pp. 167
Author(s):  
Ni Nyoman Sulastri ◽  
Shelyn Gehle

The purpose of this study was to maintain minimum moisture content for switchgrass bales that were inoculated with Pleurotus ostreatus, a white-rot fungus, in order to start the breakdown of lignin for conversion to ethanol. The moisture content was to be maintained above 50%, which would be monitored using load cells to determine the weight. Three bales were used, and thermocouple wires and hose system were placed at four points inside each bale. In addition, the ambient temperature and relative humidity inside the building were monitored. Bales were inoculated with 1%, 2%, and 3% grain spawn by mass.  The inoculation was carried out by taking the bale apart in four places and sprinkling or spreading the fungal spawn over the bale. In order to continuously record the voltage readings from the strain gauges, NI USB-6225 data logger and National Instruments’ LabVIEW program was used to record and control the system. The develop automatic weighing and watering system had been able to maintain the bale moisture within the acceptable range and the fungus were observed growing.  Some issues related to voltage readings and uniformity of water distribution must be addressed for future work.


Holzforschung ◽  
2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Marcos Paulo Vicentim ◽  
André Ferraz

Abstract The effect of different culture conditions have been evaluated concerning the extracellular enzyme activities of the white-rot fungus Ceriporiopsis subvermispora growing on Eucalyptus grandis wood. The consequence of the varied fungal pretreatment on a subsequent chemithermomechanical pulping (CTMP) was addressed. In all cultures, manganese peroxidase (MnP) and xylanase were the predominant extracellular enzymes. The biopulping efficiency was evaluated based on the amount of fiber bundles obtained after the first fiberizing step and the fibrillation levels of refined pulps. It was found that the MnP levels in the cultures correlated positively with the biopulping benefits. On the other hand, xylanase and total oxalate levels did not vary significantly. Accordingly, it was not possible to determine whether MnP accomplishes the effect alone or depends on synergic action of other extracellular agents. Pulp strength and fiber size distribution were also evaluated. The average fiber length of CTMP pulps prepared from untreated wood chips was 623 μm. Analogous values were observed for most of the biopulps; however, significant amounts of shorter fibers were found in the biopulp prepared from wood chips biotreated in cultures supplemented with glucose plus corn-steep liquor. Despite evidence of reduced average fiber length, biopulps prepared from these wood chips presented the highest improvement in tensile indexes (+28% at 23° Schopper-Riegler).


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