Effect Of Fungal Pretreatment Research Articles

Effect of fungal pretreatment by Pycnoporus sanguineus and Trichoderma longibrachiatum on the anaerobic digestion of rice straw

Rice straw is composed of complex lignocellulosic biomass, representing a major obstacle in its conversion to bioenergy. The objective of this study was to evaluate the usefulness of less explored fungal strains Trichoderma longibrachiatum (TL) and Pycnoporus sanguineus (PS) in improving hydrolysis and bioavailability of rice straw in anaerobic digestion (AD). The fungal treatment of rice straw for 10 days by PS and TL increased biogas production by 20.79% and 17.85% and reduced soluble chemical oxygen demand (sCOD) by 71.43% and 64.70%, respectively. The AD samples containing fungal-treated rice straw showed higher lignocellulolytic enzyme activities contributing to better process performance. The taxonomic profile of microbial communities in treated samples showed increased diversity that could sustain consistent system performance and exhibit enhanced resilience against pH fluctuations. Metagenomic analysis revealed 60.82% increase in Proteobacteria in PS and 11.58% increase in Bacteroidetes in TL-treated rice straw samples resulting in improved hydrolysis.

Effect of fungal pretreatment on Solanum nigrum L. leaves biomass aimed at the bioadsorption of heavy metals

Environmental degradation due to water pollution, air pollution and soil pollution has a detrimental effect and create ecological imbalance. These factors are also responsible for the large scale introduction of heavy metal ions into the environment. Conventional treatment methods for the removal of heavy metal ions are not so advantageous as these are highly expensive and also produces toxicant. Keeping this view in the mind, the present study was framed to determine the biosorption of heavy metal ions using Solanum nigrum L. leaf biomass alone and also with Aspergillus oryzae treated S. nigrum leaf biomass. Solanum nigrum L. leaf biomass was used as biosorbent for the biosorption of cobalt, copper, iron,lead and zinc.Unaided S. nigrum leaf biomass was the better absorbant of lead (Pb) whereas when inoculated with A. oryzae cobalt (Co) was more biosorbed than any other heavy metal. Overall, the results of the present study propose that the traditional plant S. nigrum could be used for the bioadsorption of heavy metals.

Fungal Pretreatment and Enzymatic Hydrolysis of Genetically-modified Populus trichocarpa

Fungal pretreatment of Populus trichocarpa wood genetically modified to reduce lignin and alter lignin chemistry is investigated for its effectiveness as an alternative to common pretreatment methods. The goal of this work is to improve biomass utilization for biofuel and biochemical applications by increasing sugar release. Sugar release after enzymatic hydrolysis was measured after various biomass pretreatments (including wood-rot fungus, hot water, and dilute acid). In the wildtype, and in constructs downregulated in PAL, 4CL, and C3H, the fungal pretreatment resulted in substantial improvements in sugar yields, up to 2.4-fold increase in glucose yield and 6-fold increase in xylose yield after enzymatic hydrolysis compared to the unpretreated control. However, the effects of fungal pretreatment were inconsistent, and in genetic lines down-regulated in 4CL, CCoAOMT, CAld5H, and C3H, fungal pretreatment yielded similar or decreased sugar release after enzymatic hydrolysis.

Fungal pretreatment and enzymatic hydrolysis of genetically-modified Populus trichocarpa

Fungal pretreatment of Populus trichocarpa wood genetically modified to reduce lignin and alter lignin chemistry is investigated for its effectiveness as an alternative to common pretreatment methods. The goal of this work is to improve biomass utilization for biofuel and biochemical applications by increasing sugar release. Sugar release after enzymatic hydrolysis was measured after various biomass pretreatments (including wood-rot fungus, hot water, and dilute acid). In the wildtype, and in constructs downregulated in PAL, 4CL, and C3H, the fungal pretreatment resulted in substantial improvements in sugar yields, up to 2.4-fold increase in glucose yield and 6-fold increase in xylose yield after enzymatic hydrolysis compared to the unpretreated control. However, the effects of fungal pretreatment were inconsistent, and in genetic lines down-regulated in 4CL, CCoAOMT, CAld5H, and C3H, fungal pretreatment yielded similar or decreased sugar release after enzymatic hydrolysis.

Comparative study of changes in composition and structure during sequential fungal pretreatment of non-sterile lignocellulosic feedstocks

Fungal pretreatment with the white rot fungus Ceriporiopsis subvermispora was performed under non-sterile conditions for four different feedstocks, corn stover, miscanthus, softwood, and hardwood, using a sequential inoculation process that employed fungal-colonized feedstock as inoculum. Fungal pretreatment improved the enzymatic digestibility of unsterilized hardwood, softwood, and miscanthus after the first generation of the sequential process, increasing the glucose yield by 2-, 3- and 4.5- fold, and the xylose yield by 9-, 7- and 10- fold, respectively. However, the fungal pretreatment of unsterilized feedstocks was unsuccessful for corn stover throughout the sequential process and for all feedstocks for the second and third generation. Modifications in feedstock structure and composition were analyzed using microscopy, spectroscopy, and thermogravimetric analysis, and showed that the effects of fungal pretreatment with C. subvermispora were feedstock-dependent. A significant fungal colonization was observed in all the fungal pretreated feedstocks, but an extensive cell wall degradation was only detected in miscanthus and hardwood. Lignin-to-cellulose ratio decreased in all successful fungal pretreated feedstocks, but the lignin units (syringyl, guaiacyl, or p-hydroxyphenyl units) that were preferentially degraded varied with each feedstock. Interestingly, C. subvermispora was able to degrade terpenes from the pine resin during the fungal pretreatment of pine wood (softwood).

Evaluation of fungal degradation of wheat straw cell wall using different analytical methods from ruminant nutrition perspective.

BACKGROUNDWhite rot fungi have been used to improve the nutritive value of lignocellulose for ruminants. In feed analysis, the Van Soest method is widely used to determine the cell wall contents. To assess the reliability of this method (Method A) for determination of cell wall contents in fungal‐treated wheat straw, we compared a combined monosaccharide analysis and pyrolysis coupled to gas chromatography with mass spectrometry (Py‐GC/MS) (Method B). Ruminal digestibility, measured as in vitro gas production (IVGP), was subsequently used to examine which method explains best the effect of fungal pretreatment on the digestibility of wheat straw.RESULTSBoth methods differed considerably in the mass recoveries of the individual cell wall components, which changed on how we assess their degradation characteristics. For example, Method B gave a higher degradation of lignin (61.9%), as compared to Method A (33.2%). Method A, however, showed a better correlation of IVGP with the ratio of lignin to total structural carbohydrates, as compared to Method B (Pearson's r of −0.84 versus −0.69). Nevertheless, Method B provides a more accurate quantification of lignin, reflecting its actual modification and degradation. With the information on the lignin structural features, Method B presents a substantial advantage in understanding the underlying mechanisms of lignin breakdown. Both methods, however, could not accurately quantify the cellulose contents – among others, due to interference of fungal biomass.CONCLUSIONMethod A only accounts for the recalcitrant residue and therefore is more suitable for evaluating ruminal digestibility. Method B allows a more accurate quantification of cell wall, required to understand and better explains the actual modification of the cell wall. The suitability of both methods, therefore, depends on their intended purposes. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Anaerobic digestion of lignocellulosic biomasses pretreated with Ceriporiopsis subvermispora

Fungal pretreatment by Ceriporiopsis subvermispora of two forest residues (hazel and acacia branches) and two agricultural lignocellulosic residues (barley straw and sugarcane bagasse) were studied as a pretreatment to improve their subsequent anaerobic digestion for methane production. Biomass samples were grinded to 2 ranges of particle sizes (<4 or 1 mm), autoclaved, inoculated with two strains of C. subvermispora (ATCC 90467 and ATCC 96608) and incubated at 28 °C for 28 days. The effects of fungal pretreatment were assessed by analyzing the samples before and after incubations for dry solids mass, biochemical composition, bio-methane production (BMP) and availability of cellulose to hydrolysis. The production of ligninolytic enzymes MnP and/or laccase was observed with both strains during incubation on most of the samples tested. It almost doubled the hazel branches BMP per unit mass of dry solids but did not improve however the BMP of the agricultural residues and acacia branches. These observations were explained by the fact that although both strains were able to degrade 20–25% of lignin in <1 mm and <4 mm hazel branches samples, none of them was successful however to significantly degrade lignin in the other samples, except for sugarcane bagasse.

Digestibility of Betung Bamboo Fiber Following Fungal Pretreatment

This research evaluated the effect of fungal pretre atment of betung bamboo fibers and enzymatic- and microwaveassisted hydrolysis on the reducing sugar yield. Th e enzymatic hydrolysis of the pretreated biomass wa s carried out with cellulase and 10 and 20 FPU/g of substrate in a shaking incubator at 50 °C and 150 rpm for 48 h. The sulfuric acid concentration used in the microwave-assisted acid h ydrolysis was 1.0, 2.5, and 5%, either with or with out the addition of activated carbon. Microwave irradiation (330 Wat t) was applied for 5‐12.5 min. The yield of reducin g sugar was better with the microwave-assisted acid hydrolysis, and the yield tended to increase with an increase in the irradiation time. Based on the dry weight of the initial biomas s (bamboo), pretreatment with 5% inoculum loading resulted in a higher reducing sugar yield (17.06%) than with 10% inoculum loading (14.54%). At a 1% acid concentration, the formation of brown compounds decreased, followed by a reduction in the reducing sugar yield. The addit ion of activated carbon at a 1% acid concentration seemed to be of no benefit with respect to the yield in th e microwaveassisted acid hydrolysis. The pretreatment with the 5% inoculum loading for 12.5 min at 1% acid concentration resulted in the highest reducing sugar yield. Under these co nditions, the yield was 6.3-fold that of the reduci ng sugar yield using 20 FPU/g of cellulase. The rate of bamboo hollocell ulose hydrolysis reached 22.75% of the maximum theoretical reducing sugar reducing sugar of dry biomass.

Effects of fungal pretreatment and steam explosion pretreatment on enzymatic saccharification of plant biomass

The effects of consecutive treatments by a lignin-degrading fungus Phanerochaete chrysosporium and by steam explosion for the enzymatic saccharification of plant biomass were studied experimentally, and the optimal operational conditions for obtaining the maximum saccharification were evaluated. Beech wood-meal was treated by the fungus for 98 days and then by high steam temperatures of 170-230 degrees C with steaming times of 0-10 min. The treatment of the wood-meal by fungus prior to steam explosion enhanced the saccharification of wood-meal. The treated wood-meal was separated into holo-cellulose, water soluble material, methanol soluble lignin, and Klason lignin. The saccharification decreased linearly with the increase in the amount of Klason lignin. It was estimated by the equation for the saccharification of exploded wood-meal expressed as a function of steam temperature and steaming time that the maximum saccharification of wood-meal was obtained by consecutive treatments such as fungal treatment for 28 days and then steam explosion at a steam temperature of 215 degrees C and a steaming time of 6.5 min. (c) 1995 John Wiley & Sons, Inc.

Decrease in Toxicity of Pentachlorophenol and Toluene to Growth of Selected Microbial Consortia and Activated Sludge by Pretreatment with Phanerochaete chrysosporium

The white rot fungus Phanerochaete chrysosporium can degrade toxic compounds under specific nutrient conditions. This attribute was utilized in order to determine the effect of fungal pretreatment on model compounds pentachlorophenol and toluene. The fungal culture was purchased from ATCC, cultured on dextrose agar, and the mycelia harvested to degrade the model compounds. P. chrysosporium was able to degrade up to 74% of initial pentachlorophenol concentration in eight days and up to 31% initial toluene in 31 hours. Specific growth rates of activated sludge and selected microbial consortia were determined on untreated and fungal-pretreated parent model compounds. Specific growth rates for activated sludge and selected microbial consortia were enhanced by fungal pretreatment of both model compounds. Specific growth rates indicated more efficient use of toluene by activated sludge than by toluene-selected microbial consortia, while pentachlorophenol- selected microbial consortia exhibited more favorable growth rates on pentachlorophenol than did activated sludge. Pretreatment results indicated that the toxicity of model compounds was reduced by fungal pretreatment. The growth rates were compared and used as an indication of toxicity reduction which can be exploited at contaminated waste sites or at industrial pretreatment facilities.