Enhanced degradation of ammonium-pretreated wheat straw by lignocellulolytic Streptomyces spp.

1992 ◽  
Vol 38 (10) ◽  
pp. 1022-1025 ◽  
Author(s):  
Marina Basaglia ◽  
Giuseppe Concheri ◽  
Stefano Cardinali ◽  
Maria B. Pasti-Grigsby ◽  
Marco P. Nuti

Eleven actinomycetes, isolated from the gut of worker termites (Macrotermes, Armitermes, Microcerotermes, Odontotermes), were identified as Streptomyces chromofuscus, S. chromogenus, S. diastaticus, and S. rochei. Their ability to grow on natural lignocellulosic substrates was tested in solid state fermentation experiments using wheat straw (C/N = 49.8) as a sole carbon source. Weight loss was 4.7–20.9% of the initial substrate, after 5 weeks at 30 °C; lignin and cellulose content decreased 2.0–16.1 and 3.5–32.9%, respectively. When the 11 Streptomyces were grown on wheat straw pretreated with (NH4)HCO3 (C/N = 28.2), weight loss was 9.3–29.9% of the initial substrate, indicating an overall enhancement of lignocellulose degradation. Weight, lignin, and cellulose losses were enhanced when S. chromofuscus (strain A2 and A11) and S. rochei A4 were grown on pretreated wheat straw instead of the untreated substrate. With S. rochei A10 the weight loss and lignin degradation were enhanced, while cellulolysis was slightly depressed. Weight loss and cellulose degradation were both enhanced when the remaining strains were grown on pretreated wheat straw. In this case, lignin degradation was depressed (S. chromofuscus A6 and A8, S. diastaticus A12, S. rochei A14) or remained essentially the same (S. diastaticus A3 and S. chromogenus A7). Key words: Streptomyces, wheat straw, degradation, lignin, cellulose.

2011 ◽  
Vol 347-353 ◽  
pp. 2996-3000 ◽  
Author(s):  
Jun Ling Niu ◽  
Lei Liu ◽  
Quan Guo Zhang

The study on the changes of composition and content reducing sugar of wheat straw after pretreated with composite microbial system for degrading cellulose was carried out, and the experimental study on the dry anaerobic fermentation of the pretreated wheat straw was followed. The results showed for pretreated wheat straw there is a significant increase for the amount of reducing sugar, the hemicellulose content decreased 49.43%, the cellulose content also decreased a little, but the lignin content had little change. For the dry anaerobic fermentation process, the reaction is started fast, the pH values declined faster in the prophase for the pretreated straw, the mixed biogas production and the methane content have been increased over that of non-pretreated wheat straw, and the gas was produced more steadily. The accumulated gas production had been to 4810mL, which was more than the non pretreated straw, before the maximum gas production was appeared.


2013 ◽  
Vol 164 (1) ◽  
pp. 50-58 ◽  
Author(s):  
Borbála Erdei ◽  
Balázs Frankó ◽  
Mats Galbe ◽  
Guido Zacchi

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%.


2018 ◽  
Vol 115 ◽  
pp. 139-148 ◽  
Author(s):  
Yiqing Yao ◽  
Andre David Bergeron ◽  
Maryam Davaritouchaee

2013 ◽  
Vol 853 ◽  
pp. 253-259 ◽  
Author(s):  
Guan Rong Wang ◽  
Yu Lin Duan

Lignocellulosic material is the earth's most abundant renewable resource, but because of its stable and complex structure, it is not easy for depredating and utilizing for a long time. Rumen can degrade lignocellulose, and is one of nature's most efficient fermentation fermenter; to be study rumen microorganisms has the potential to provide valuable solutions to renewable energy, processing of agricultural waste, organic waste etc. Research methods vary from screening of cellulose-degradation bacteria, enzymatic characterization, to the use of metagenomics technology to get a large number of genes directly from the rumen. This article reviews the characteristics, mechanism and contribution of different rumen microbial in degradation of lignocellulose, as well as the research progress of enzymatic characterization and rumen microbial metagenomics.


1983 ◽  
Vol 61 (4) ◽  
pp. 1194-1198 ◽  
Author(s):  
John B. Sutherland ◽  
Anthony L. Pometto III ◽  
Don L. Crawford

Eighteen strains of fungi in the genus Fusarium, including varieties of F. episphaeria, F. lateritium, F. moniliforme, F. nivale, F. oxysporum, F. rigidiusculum, F. roseum, F. solani, and F. tricinctum, slowly degraded lignocelluloses from blue spruce (Picea pungens) and wheat (Triticum aestivum). When grown with [lignin-14C]lignocellulose from blue spruce, 15 of the Fusarium strains converted 2.2 to 4.3% of the [14C]lignin in 60 days to 14CO2 and 3.9 to 8.4% to labeled water-soluble products. When grown with unlabeled lignocellulose from wheat straw, the strains caused total weight losses in 60 days of 7 to 25%, acid-insoluble (Klason) lignin losses of 2 to 17%, and carbohydrate losses of 3 to 33%. Crude protein contents of degraded wheat-straw lignocellulose samples were 3.2 to 5.1%. Among the aromatic degradation products from wheat-straw lignocellulose degraded by different strains, as shown by gas chromatography, were p-coumaric acid, vanillic acid, vanillin, syringaldehyde, and p-hydroxybenzaldehyde.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Dong Tian ◽  
Yiyi Chen ◽  
Fei Shen ◽  
Maoyuan Luo ◽  
Mei Huang ◽  
...  

Abstract Background Peroxyacetic acid involved chemical pretreatment is effective in lignocellulose deconstruction and oxidation. However, these peroxyacetic acid are usually artificially added. Our previous work has shown that the newly developed PHP pretreatment (phosphoric acid plus hydrogen peroxide) is promising in lignocellulose biomass fractionation through an aggressive oxidation process, while the information about the synergistic effect between H3PO4 and H2O2 is quite lack, especially whether some strong oxidant intermediates is existed. In this work, we reported the PHP pretreatment system could self-generate peroxyacetic acid oxidant, which mediated the overall lignocellulose deconstruction, and hemicellulose/lignin degradation. Results The PHP pretreatment profile on wheat straw and corn stalk were investigated. The pathways/mechanisms of peroxyacetic acid mediated-PHP pretreatment were elucidated through tracing the structural changes of each component. Results showed that hemicellulose was almost completely solubilized and removed, corresponding to about 87.0% cellulose recovery with high digestibility. Rather high degrees of delignification of 83.5% and 90.0% were achieved for wheat straw and corn stalk, respectively, with the aid of peroxyacetic acid oxidation. A clearly positive correlation was found between the concentration of peroxyacetic acid and the extent of lignocellulose deconstruction. Peroxyacetic acid was mainly self-generated through H2O2 oxidation of acetic acid that was produced from hemicellulose deacetylation and lignin degradation. The self-generated peroxyacetic acid then further contributed to lignocellulose deconstruction and delignification. Conclusions The synergistic effect of H3PO4 and H2O2 in the PHP solvent system could efficiently deconstruct wheat straw and corn stalk lignocellulose through an oxidation-mediated process. The main function of H3PO4 was to deconstruct biomass recalcitrance and degrade hemicellulose through acid hydrolysis, while the function of H2O2 was to facilitate the formation of peroxyacetic acid. Peroxyacetic acid with stronger oxidation ability was generated through the reaction between H2O2 and acetic acid, which was released from xylan and lignin oxidation/degradation. This work elucidated the generation and function of peroxyacetic acid in the PHP pretreatment system, and also provide useful information to tailor peroxide-involved pretreatment routes, especially at acidic conditions. Graphical abstract


2017 ◽  
Vol 184 (1) ◽  
pp. 48-62 ◽  
Author(s):  
Ramkumar B. Nair ◽  
Maryam M. Kabir ◽  
Patrik R. Lennartsson ◽  
Mohammad J. Taherzadeh ◽  
Ilona Sárvári Horváth

AbstractIntegration of wheat straw for a biorefinery-based energy generation process by producing ethanol and biogas together with the production of high-protein fungal biomass (suitable for feed application) was the main focus of the present study. An edible ascomycete fungal strain Neurospora intermedia was used for the ethanol fermentation and subsequent biomass production from dilute phosphoric acid (0.7 to 1.2% w/v) pretreated wheat straw. At optimum pretreatment conditions, an ethanol yield of 84 to 90% of the theoretical maximum, based on glucan content of substrate straw, was observed from fungal fermentation post the enzymatic hydrolysis process. The biogas production from the pretreated straw slurry showed an improved methane yield potential up to 162% increase, as compared to that of the untreated straw. Additional biogas production, using the syrup, a waste stream obtained post the ethanol fermentation, resulted in a combined total energy output of 15.8 MJ/kg wheat straw. Moreover, using thin stillage (a waste stream from the first-generation wheat-based ethanol process) as a co-substrate to the biogas process resulted in an additional increase by about 14 to 27% in the total energy output as compared to using only wheat straw-based substrates.


2010 ◽  
Vol 85 (9) ◽  
pp. 1291-1297 ◽  
Author(s):  
Pablo Alvira ◽  
María José Negro ◽  
Felicia Sáez ◽  
Mercedes Ballesteros

2020 ◽  
Vol 10 (21) ◽  
pp. 7638
Author(s):  
Vasile-Florin Ursachi ◽  
Gheorghe Gutt

The aim of this study is to find the optimal pretreatment conditions and hydrolysis in order to obtain a high yield of bioethanol from wheat straw. The pretreatments were performed with different concentrations of sulphuric acid 1, 2 and 3% (v/v), and were followed by an enzymatic hydrolysis that was performed by varying the solid-to-liquid ratio (1/20, 1/25 and 1/30 g/mL) and the enzyme dose (30/30 µL/g, 60/60 µL/g and 90/90 µL/g Viscozyme® L/Celluclast® 1.5 L). This mix of enzymes was used for the first time in the hydrolysis process of wheat straws which was previously pretreated with dilute sulfuric acid. Scanning electron microscopy indicated significant differences in the structural composition of the samples because of the pretreatment with H2SO4 at different concentrations, and ATR-FTIR analysis highlighted the changes in the chemical composition in the pretreated wheat straw as compared to the untreated one. HPLC-RID was used to identify and quantify the carbohydrates content resulted from enzymatic hydrolysis to evaluate the potential of using wheat straws as a raw material for production of cellulosic ethanol in Romania. The highest degradation of lignocellulosic material was obtained in the case of pretreatment with 3% H2SO4 (v/v), a solid-to-liquid ratio of 1/30 and an enzyme dose of 90/90 µL/g. Simultaneous saccharification and fermentation were performed using Saccharomyces cerevisiae yeast, and for monitoring the fermentation process a BlueSens equipment was used provided with ethanol, O2 and CO2 cap sensors mounted on the fermentation flasks. The highest concentration of bioethanol was obtained after 48 h of fermentation and it reached 1.20% (v/v).


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