The production of ligninolytic enzymes and protease by Phanerochaete chrysosporium was investigated under different culture conditions. Different amounts of medium were employed in free and immobilized culture, togeth...The production of ligninolytic enzymes and protease by Phanerochaete chrysosporium was investigated under different culture conditions. Different amounts of medium were employed in free and immobilized culture, together with two kinds of medium with different C/N ratios. Little lignin peroxidase (LIP) (〈 2 U/L) was detected in free culture with nitrogen-limited medium (C/N ratio: 56/2.2, in mmol/L), while manganese peroxidase (MnP) maximum activity was 231 and 240 U/L in 50 and 100 ml medium culture, respectively. Immobilized culture with 50 ml nitrogen-limited medium gave the highest MnP and LiP production with the maximum values of 410 and 721 U/L separately on the day 5; however, flasks containing 100 ml nitrogen-limited medium only produced less MnP with a peak value of 290 U/L. Comparatively, carbon-limited medium (C/N ratio: 28/44, in mmol/L) was adopted in culture but produced little MnP and LiE Medium type had the greatest impact on protease production. Large amount of protease was produced due to glucose limitation. Culture type and medium volume influence protease activity corporately by affecting oxygen supply. The results implied shallow immobilized culture was a possible way to gain high production of ligninolytic enzymes.展开更多
The present work studied the influence of glucose feeding on the ligninolytic enzyme production of Phanerochaete chrysosporium in a nitrogen-limited(C/N ratio is 56/8.8 mmol/L)medium.Several sets of shaking flask expe...The present work studied the influence of glucose feeding on the ligninolytic enzyme production of Phanerochaete chrysosporium in a nitrogen-limited(C/N ratio is 56/8.8 mmol/L)medium.Several sets of shaking flask experiments were conducted.The results showed that 2 g/L glucose feeding on the first day of the culture(24 h after the inoculation)stimulated both fungal biomass growth and enzyme production.The manganese peroxidase(MnP)activ-ity was 2.5 times greater than that produced in cultures with-out glucose feeding.Furthermore,the glucose feeding mode in fed-batch culture was also investigated.Compared to cul-tures with glucose feeding every 48 h,cultures with glucose feeding of 1.5 g/L(final concentration)every 24 h produced more enzymes.The peak and total yield of MnP activity were 2.7 and 3 times greater compared to the contrast culture,respectively,and the enzyme was kept stable for 4 days with an activity of over 200 U/L.展开更多
Manganese peroxidase (MnP) is a ligninolytic enzyme that is involved in the removal of lignin from the cell wall of plants. This removal facilitates the access of hydrolytic enzymes to the carbohydrate polymers that a...Manganese peroxidase (MnP) is a ligninolytic enzyme that is involved in the removal of lignin from the cell wall of plants. This removal facilitates the access of hydrolytic enzymes to the carbohydrate polymers that are hydrolyzed to simple sugars, which allows the subsequent fermentation to obtain bioproducts, such as ethanol. In this work, response surface methodology (RSM) was employed to optimize the culture conditions on unexpensive substrate for MnP secretion by Trametes villosa. Three independent variables were evaluated (i.e., temperature, moisture content and pH). The crude extract containing MnP was used in the delignification experiment and it caused a reduction in lignin content for all residues tested: 35.05 ± 1.45 (%) for the sugar cane bagasse;63.11 ± 0.06 (%) for the sisal fiber and 39.61 ± 0.39 (%) for the coconut shell, under the reaction conditions tested after 4 hours of fermentation. The preliminary results exhibited the potential application of this enzyme in the removal of lignin from plant residues. However, the conditions should be evaluated and optimized for each residue type.展开更多
A 120-day experiment was conducted to compare the removal of polycyclic aromatic hydrocarbons(PAHs) from agricultural soil after natural attenuation(NA), phytoremediation(P), mycoremediation(M), and plant-assisted myc...A 120-day experiment was conducted to compare the removal of polycyclic aromatic hydrocarbons(PAHs) from agricultural soil after natural attenuation(NA), phytoremediation(P), mycoremediation(M), and plant-assisted mycoremediation(PAM) approaches in relation to the extracellular enzyme activities in soil. The NA treatment removed the total soil PAH content negligibly. The P treatment using maize(Zea mays) enhanced only the removal of low and medium molecular PAHs. The Pleurotus ostreatus cultivated on 30–50 mm wood chip substrate used in M treatment was the most successful in the removal of majority PAHs. Therefore,significantly(p < 0.05) highest total PAH removal by 541.4 μg/kg dw(dry weight)(36%) from all tested M treatments was observed. When using the same fungal substrate together with maize in PAM treatment, the total PAH removal was not statistically different from the previous M treatment. However, the maize-assisted mycoremediation treatment significantly boosted fungal biomass, microbial and manganese peroxidase activity in soil which strongly correlated with the removal of total PAHs. The higher PAH removal in that PAM treatment could be reflected in the following post-harvest time. Our suggested M and PAM approaches could be promising in situ bioremediation strategies for PAH-contaminated soils.展开更多
Armillaria sp. F022, a white rot fungus isolated from tropical rain forest (Samarinda, Indonesia) was used to biodegrade naphthalene in cultured medium. Transformation of naphthalene by Armillaria sp. F022 which is ...Armillaria sp. F022, a white rot fungus isolated from tropical rain forest (Samarinda, Indonesia) was used to biodegrade naphthalene in cultured medium. Transformation of naphthalene by Armillaria sp. F022 which is able to use naphthalene, a two ring-polycyclic aromatic hydrocarbon (PAH) as a source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that Armillaria sp. F022 initiates its attack on naphthalene by dioxygenation at its C-1 and C-4 positions to give 1,4-naphthoquinone. The intermediate 2-hydroxybenzaldebyde and salicylic acid, and the characteristic of the meta-cleavage of the resulting diol were identified in the long-term incubation. A part from typical metabolites of naphthalene degradation known from mesophiles, benzoic acid was identified as the next intermediate for the naphthalene pathway of this Armillaria sp. F022. Neither phthalic acid, catechol and cis, cis-muconic acid metabolites were detected in culture extracts. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by ArmiUaria sp. F022 were detected during the incubation.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.50478010).
文摘The production of ligninolytic enzymes and protease by Phanerochaete chrysosporium was investigated under different culture conditions. Different amounts of medium were employed in free and immobilized culture, together with two kinds of medium with different C/N ratios. Little lignin peroxidase (LIP) (〈 2 U/L) was detected in free culture with nitrogen-limited medium (C/N ratio: 56/2.2, in mmol/L), while manganese peroxidase (MnP) maximum activity was 231 and 240 U/L in 50 and 100 ml medium culture, respectively. Immobilized culture with 50 ml nitrogen-limited medium gave the highest MnP and LiP production with the maximum values of 410 and 721 U/L separately on the day 5; however, flasks containing 100 ml nitrogen-limited medium only produced less MnP with a peak value of 290 U/L. Comparatively, carbon-limited medium (C/N ratio: 28/44, in mmol/L) was adopted in culture but produced little MnP and LiE Medium type had the greatest impact on protease production. Large amount of protease was produced due to glucose limitation. Culture type and medium volume influence protease activity corporately by affecting oxygen supply. The results implied shallow immobilized culture was a possible way to gain high production of ligninolytic enzymes.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20577028).
文摘The present work studied the influence of glucose feeding on the ligninolytic enzyme production of Phanerochaete chrysosporium in a nitrogen-limited(C/N ratio is 56/8.8 mmol/L)medium.Several sets of shaking flask experiments were conducted.The results showed that 2 g/L glucose feeding on the first day of the culture(24 h after the inoculation)stimulated both fungal biomass growth and enzyme production.The manganese peroxidase(MnP)activ-ity was 2.5 times greater than that produced in cultures with-out glucose feeding.Furthermore,the glucose feeding mode in fed-batch culture was also investigated.Compared to cul-tures with glucose feeding every 48 h,cultures with glucose feeding of 1.5 g/L(final concentration)every 24 h produced more enzymes.The peak and total yield of MnP activity were 2.7 and 3 times greater compared to the contrast culture,respectively,and the enzyme was kept stable for 4 days with an activity of over 200 U/L.
文摘Manganese peroxidase (MnP) is a ligninolytic enzyme that is involved in the removal of lignin from the cell wall of plants. This removal facilitates the access of hydrolytic enzymes to the carbohydrate polymers that are hydrolyzed to simple sugars, which allows the subsequent fermentation to obtain bioproducts, such as ethanol. In this work, response surface methodology (RSM) was employed to optimize the culture conditions on unexpensive substrate for MnP secretion by Trametes villosa. Three independent variables were evaluated (i.e., temperature, moisture content and pH). The crude extract containing MnP was used in the delignification experiment and it caused a reduction in lignin content for all residues tested: 35.05 ± 1.45 (%) for the sugar cane bagasse;63.11 ± 0.06 (%) for the sisal fiber and 39.61 ± 0.39 (%) for the coconut shell, under the reaction conditions tested after 4 hours of fermentation. The preliminary results exhibited the potential application of this enzyme in the removal of lignin from plant residues. However, the conditions should be evaluated and optimized for each residue type.
基金supported by the Ministry of Agriculture of the Czech Republic (QK1710379)the University-wide internal grant agency of CULS Prague – CIGA (20172018)
文摘A 120-day experiment was conducted to compare the removal of polycyclic aromatic hydrocarbons(PAHs) from agricultural soil after natural attenuation(NA), phytoremediation(P), mycoremediation(M), and plant-assisted mycoremediation(PAM) approaches in relation to the extracellular enzyme activities in soil. The NA treatment removed the total soil PAH content negligibly. The P treatment using maize(Zea mays) enhanced only the removal of low and medium molecular PAHs. The Pleurotus ostreatus cultivated on 30–50 mm wood chip substrate used in M treatment was the most successful in the removal of majority PAHs. Therefore,significantly(p < 0.05) highest total PAH removal by 541.4 μg/kg dw(dry weight)(36%) from all tested M treatments was observed. When using the same fungal substrate together with maize in PAM treatment, the total PAH removal was not statistically different from the previous M treatment. However, the maize-assisted mycoremediation treatment significantly boosted fungal biomass, microbial and manganese peroxidase activity in soil which strongly correlated with the removal of total PAHs. The higher PAH removal in that PAM treatment could be reflected in the following post-harvest time. Our suggested M and PAM approaches could be promising in situ bioremediation strategies for PAH-contaminated soils.
基金supported by Research University Grant of Universiti Teknologi Malaysia(No. Q.J13000.7122.00J31)
文摘Armillaria sp. F022, a white rot fungus isolated from tropical rain forest (Samarinda, Indonesia) was used to biodegrade naphthalene in cultured medium. Transformation of naphthalene by Armillaria sp. F022 which is able to use naphthalene, a two ring-polycyclic aromatic hydrocarbon (PAH) as a source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that Armillaria sp. F022 initiates its attack on naphthalene by dioxygenation at its C-1 and C-4 positions to give 1,4-naphthoquinone. The intermediate 2-hydroxybenzaldebyde and salicylic acid, and the characteristic of the meta-cleavage of the resulting diol were identified in the long-term incubation. A part from typical metabolites of naphthalene degradation known from mesophiles, benzoic acid was identified as the next intermediate for the naphthalene pathway of this Armillaria sp. F022. Neither phthalic acid, catechol and cis, cis-muconic acid metabolites were detected in culture extracts. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by ArmiUaria sp. F022 were detected during the incubation.