Sequential white-rot and brown-rot fungal pretreatment of wheat straw as a promising alternative for complementary mild treatments

2018 ◽  
Vol 79 ◽  
pp. 240-250 ◽  
Author(s):  
Edward Hermosilla ◽  
Olga Rubilar ◽  
Heidi Schalchli ◽  
Ayla Sant'Ana da Silva ◽  
Viridiana Ferreira-Leitao ◽  
...  
2021 ◽  
Author(s):  
Aleksandar Knežević ◽  
Ivana Đokić ◽  
Tomislav Tosti ◽  
Slađana Popović ◽  
Dušanka Milojković-Opsenica ◽  
...  

Abstract The aim of the study was comparative analysis of degradation of wheat straw lignin by white-rot fungi and its implications on the efficiency of enzymatic hydrolysis of holocellulose. Cyclocybe cylindracea, Ganoderma resinaceum, Irpex lacteus, Pleurotus ostreatus and Trametes versicolor were the species studied. Peroxidases were predominantly responsible for lignin degradation even though high laccase activities were detected, except in the case of Irpex lacteus where laccase activity was not detected. Studied fungal species showed various ability to degrade lignin in wheat straw which further affected release of reducing sugars during enzymatic saccharification. The highest rate of lignin degradation was noticed in sample pretreated with Irpex lacteus (50.9 ± 4.1%). Among all tested species only Ganoderma resinaceum was suitable lignin degrader with the 2-fold higher hydrolysis yield (51.1 ± 4.7%) than in the control, and could have significant biotechnological application due to lower cellulose loss. A key mechanism of carbohydrate component convertibility enhancement was lignin removal in the biomass. Long time consumption, the low sugar yields and unpredictable fungal response still remain the challenge of the fungal pretreatment process.


BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3978-3990
Author(s):  
Meng Li ◽  
Zhinan Wang ◽  
Jin Sun ◽  
Wanjuan Chen ◽  
Xianfeng Hu ◽  
...  

The thermogravimetric properties and chemical characterization of rice straw (RS) pretreated by mixed culture of white-rot fungi Phanerochaete chrysosporium (P. chrysosporium) and brown-rot fungi Gloeophyllum trabeum (G. trabeum) were investigated. The mixed fungal pretreatment showed a synergistic effect, which resulted in an energy-efficient pyrolysis of pretreated rice straw. The differences in thermochemical conversion of rice straw before and after fungal pretreatment were investigated using thermogravimetric analysis and the Flynn–Wall–Ozawa (FWO) method. Furthermore, the pretreated samples were also analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) to illuminate the changes in chemical composition and pyrolysis behavior. Compared to single fungal pretreatment, the mixed fungal pretreatment worked better and exhibited great potential in biomass pyrolysis.


2020 ◽  
Vol 8 (2) ◽  
pp. 18-34
Author(s):  
Yanuartono - ◽  
Hary - Purnamaningsih ◽  
Soedarmanto - Indarjulianto ◽  
Alfarisa - Nururrozi ◽  
Slamet - Raharjo ◽  
...  

ABSTRACTAn improvement in animal feeding is one of the important and basic conditions for the better management of farming of animals. It was recognized that poor quality of the feed is mainly responsible for the poor animal performance. For most farming practices, feed is an expensive component in livestock farming. Alternative feed can be obtained from agricultural by-products with huge amount around the world. The main factors limiting the utilization of agricultural by-products like paddy straw, wheat straw and corn stover are their low digestibility, low protein content and some time low palatability. However, the nutritive value of the agricultural by-products can be enhanced through their biological treatment and hence play an important role to meet nutrient requirements of the animals. Thus, an alternative approach is biological treatment especially fungi to increase digestibility of agricultural by-products. The use of white rot fungi, brown rot fungi and soft rot fungi that metabolize lignocelluloses is a potential biological treatment to improve the nutritional value of agricultural by-products. This paper aims to discuss the role of fungi in increasing the nutritional value of agricultural by-products like paddy straw, wheat straw and corn stover.Keywords: Agricultural by-products, Biological treatment, fungi, Lignocelluloses


2019 ◽  
Vol 26 (14) ◽  
pp. 2475-2484 ◽  
Author(s):  
Congqiang Zhang ◽  
Heng-Phon Too

Lignocellulose is the most abundant renewable natural resource on earth and has been successfully used for the production of biofuels. A significant challenge is to develop cost-effective, environmentally friendly and efficient processes for the conversion of lignocellulose materials into suitable substrates for biotransformation. A number of approaches have been explored to convert lignocellulose into sugars, e.g. combining chemical pretreatment and enzymatic hydrolysis. In nature, there are organisms that can transform the complex lignocellulose efficiently, such as wood-degrading fungi (brown rot and white rot fungi), bacteria (e.g. Clostridium thermocellum), arthropods (e.g. termite) and certain animals (e.g. ruminant). Here, we highlight recent case studies of the natural degraders and the mechanisms involved, providing new utilities in biotechnology. The sugars produced from such biotransformations can be used in metabolic engineering and synthetic biology for the complete biosynthesis of natural medicine. The unique opportunities in using lignocellulose directly to produce natural drug molecules with either using mushroom and/or ‘industrial workhorse’ organisms (Escherichia coli and Saccharomyces cerevisiae) will be discussed.


2021 ◽  
Vol 215 ◽  
pp. 106749
Author(s):  
Jialong Zhang ◽  
Lei Wang ◽  
Haoxiang Ni ◽  
Qipeng Shi ◽  
Xiaoyu Zhang ◽  
...  

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lukas Emmerich ◽  
Maja Bleckmann ◽  
Sarah Strohbusch ◽  
Christian Brischke ◽  
Susanne Bollmus ◽  
...  

Abstract Chemical wood modification has been used to modify wood and improve its decay resistance. However, the mode of protective action is still not fully understood. Occasionally, outdoor products made from chemically modified timber (CMT) show internal decay while their outer shell remains intact. Hence, it was hypothesized that wood decay fungi may grow through CMT without losing their capability to degrade non-modified wood. This study aimed at developing a laboratory test set-up to investigate (1) whether decay fungi grow through CMT and (2) retain their ability to degrade non-modified wood. Acetylated and 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) treated wood were used in decay tests with modified ‘mantle specimens’ and untreated ‘core dowels’. It became evident that white rot (Trametes versicolor), brown rot (Coniophora puteana) and soft rot fungi can grow through CMT without losing their ability to degrade untreated wood. Consequently, full volume impregnation of wood with the modifying agent is required to achieve complete protection of wooden products. In decay tests with DMDHEU treated specimens, significant amounts of apparently non-fixated DMDHEU were translocated from modified mantle specimens to untreated wood cores. A diffusion-driven transport of nitrogen and DMDHEU seemed to be responsible for mass translocation during decay testing.


Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Christian Brischke ◽  
Christian Robert Welzbacher ◽  
Andreas Otto Rapp

Abstract The suitability of a previously described high-energy multiple impact (HEMI) test for the detection of early fungal decay was examined. The HEMI test characterises the treatment severity of thermally modified wood by stressing the treated material by thousands of impacts of pounding steel balls. This method differentiates between heat treatment intensities, which are manifest as structural changes in the wood. Similar changes in wood structure are known for wood decayed by fungi. Pine (Pinus sylvestris L.) decayed by brown rot and beech (Fagus sylvatica L.) decayed by white rot were tested. Mass loss caused by fungal decay and resistance to impact milling (RIM) determined in HEMI tests were found to be highly correlated. Testing of non-degraded pine, beech, and ash (Fraxinus exelsior L.) showed only marginal effects of wood density on RIM. Furthermore, annual ring angles and RIM of spruce (Picea abies Karst.) were not correlated. Accordingly, the detection of RIM reduction in decayed wood is not masked by variations in density and orientation of the annual rings. Previous results showed no adverse effects of weathering on RIM. Thus, the detection of fungal decay with HEMI tests is feasible not only for laboratory purposes, but also for wood in outdoor applications that has already undergone weathering.


Bioethanol ◽  
2016 ◽  
Vol 2 (1) ◽  
Author(s):  
María García-Torreiro ◽  
Miguel Álvarez Pallín ◽  
María López-Abelairas ◽  
Thelmo A. Lu-Chau ◽  
Juan M. Lema

AbstractBioconversion of lignocellulosic materials into ethanol requires an intermediate pretreatment step for conditioning biomass. Sugar yields from wheat straw were previously improved by the addition of a mild alkali pretreatment step before bioconversion by the white-rot fungus Irpex lacteus. In this work, an alternative alkaline treatment, which significantly reduces water consumption, was implemented and optimized. Sugar recovery increased 117% with respect to the previously developed alkaline wash process at optimal process conditions (30°C, 30 minutes and 35.7% (w/w) of NaOH). In order to further reduce operational costs, a system for alkali recycling was implemented. This resulted in the treatment of 150% more wheat straw using the same amount of NaOH. Finally, enzymatic hydrolysis was optimized and resulted in a reduction of enzyme dose of 33%.


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