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 responses of the growth and metabolism activity of Phanerochaete chrysosporium (P. chrysosporium) to cadmium (Cd), lead (Pb) and their combined pollution stress, were investigated in plate and liquid culture...The responses of the growth and metabolism activity of Phanerochaete chrysosporium (P. chrysosporium) to cadmium (Cd), lead (Pb) and their combined pollution stress, were investigated in plate and liquid culture conditions. The diameter of colony, biomass ofP. chrysosporium, ligninolytic enzyme activities and bioaccumulation quantity of heavy metals were detected. The results indicated that Cd was more toxic than Pb to P. chrysosporium and the toxicity of Cd and Pb to P. chrysosporium was further strengthened under Cd+Pb combined pollution in different culture conditions. Heavy metals Cd and Pb had indirect influence on the production of ligninolytic enzymes by directly affecting the fungal growth and metabolic activity, and by another way in liquid culture. In addition, the results provided an evidence of the accumulation of Cd and Pb on the mycelia ofP. chrysosporium.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
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
Fluoranthene, a four-ring polycyclic aromatic hydrocarbon that is possible genotoxic in nature, has been used as an indicator for assessing polycyclic aromatic hydrocarbon (PAH)-containing pollutants. Microbial degr...Fluoranthene, a four-ring polycyclic aromatic hydrocarbon that is possible genotoxic in nature, has been used as an indicator for assessing polycyclic aromatic hydrocarbon (PAH)-containing pollutants. Microbial degradation is one of the promising methods in removing up PAH-contaminated environments. White-rot fungi have showed the ability to degrade a wide range of PAHs. This study aimed to investigate enzyme production, fungal biomass, and glucose utilization during the biodegradation process of fiuoranthene by a white-rot fungus Pleurotus pulmonarius F043 and to identify the metabolites produced in the degradation process. The extracellular ligninolytic enzyme system of the fungi, producing laccases and peroxidases, was directly linked to the biodegradation of fiuoranthene. The production of ligninolytic enzymes during fluoranthene degradation was related to an increase in the biomass of Pleurotus pulmonarius F043. Fluoranthene removal decreased with an increase in fluoranthene concentrations. The highest biomass production of Pleurotus pulmonarius F043 (〉 4 400 mg L-1) was found in the 10 mg L-1 fluoranthene culture after 30 d of incubation. Two fluoranthene metabolites, naphthalene-l,8-dicarboxylic acid and phthalic acid, were found in the process of fluoranthene degradation. Laccase was revealed as the major enzyme that played an important role in degradation process. Suitable conditions must be found to promote a successful fungal biotransformation augmentation in liquid culture.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Projects(21477027,51278176)supported by the National Natural Science Foundation of ChinaProject(2014A020216048)supported by the Science and Technology Planning Project of Guangdong Province,ChinaProject(2015M582363)supported by the China Postdoctoral Science Foundation
文摘The responses of the growth and metabolism activity of Phanerochaete chrysosporium (P. chrysosporium) to cadmium (Cd), lead (Pb) and their combined pollution stress, were investigated in plate and liquid culture conditions. The diameter of colony, biomass ofP. chrysosporium, ligninolytic enzyme activities and bioaccumulation quantity of heavy metals were detected. The results indicated that Cd was more toxic than Pb to P. chrysosporium and the toxicity of Cd and Pb to P. chrysosporium was further strengthened under Cd+Pb combined pollution in different culture conditions. Heavy metals Cd and Pb had indirect influence on the production of ligninolytic enzymes by directly affecting the fungal growth and metabolic activity, and by another way in liquid culture. In addition, the results provided an evidence of the accumulation of Cd and Pb on the mycelia ofP. chrysosporium.
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.
基金supported by the Fundamental Research Grant Scheme(FRGS)of Ministry of Education,Malaysia(No.R.J130000.7809.4F465the Science Fund of Ministry of Science,Technology and Innovation,Malaysia(No.R.J130000.7909.4S110)
文摘Fluoranthene, a four-ring polycyclic aromatic hydrocarbon that is possible genotoxic in nature, has been used as an indicator for assessing polycyclic aromatic hydrocarbon (PAH)-containing pollutants. Microbial degradation is one of the promising methods in removing up PAH-contaminated environments. White-rot fungi have showed the ability to degrade a wide range of PAHs. This study aimed to investigate enzyme production, fungal biomass, and glucose utilization during the biodegradation process of fiuoranthene by a white-rot fungus Pleurotus pulmonarius F043 and to identify the metabolites produced in the degradation process. The extracellular ligninolytic enzyme system of the fungi, producing laccases and peroxidases, was directly linked to the biodegradation of fiuoranthene. The production of ligninolytic enzymes during fluoranthene degradation was related to an increase in the biomass of Pleurotus pulmonarius F043. Fluoranthene removal decreased with an increase in fluoranthene concentrations. The highest biomass production of Pleurotus pulmonarius F043 (〉 4 400 mg L-1) was found in the 10 mg L-1 fluoranthene culture after 30 d of incubation. Two fluoranthene metabolites, naphthalene-l,8-dicarboxylic acid and phthalic acid, were found in the process of fluoranthene degradation. Laccase was revealed as the major enzyme that played an important role in degradation process. Suitable conditions must be found to promote a successful fungal biotransformation augmentation in liquid culture.
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.