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Coriolopsis trogii and Cerrena unicolor were investigated for laccase production in submerged fermentation with different nutrient medium containing metal ions and lignocellulosic materials. The maximum laccase activity of C. trogii Han751 was 8584.44 ± 98.45 U/L and was obtained from nutrient medium 7. However, the maximum laccase activity of C. unicolor Han 849 was 16144.26 ± 635.30 U/L from nutrient medium 9. Thus, the capacity of secreting laccase of C. unicolor Han 849 was superior to that of C. trogii Han751. Different fungal species have different medium components suitable for laccase production. The content of CuSO4·5H2O and MnSO4 in nutrient medium with the concentration of 0.25 g/L and 0.151 g/L, respectively, was more beneficial to C. trogii Han751 secreting laccase. However, the vital components of nutrient medium that contribute to the laccase activity of C. unicolor Han 849 were corncob, glucose, and CuSO4·5H2O, with the corresponding concentrations of 1 g/flask, 5 g/L, and 0.25 g/L, respectively. The results will contribute to the development of new methods to produce low-cost laccase.

Lignocellulosic biomass is widely used in the field of laccase production because it has the advantages of low price and easy availability. Thus, a comparative analysis was performed of the laccase secretion ability of five white-rot fungi in submerged fermentation using single or mixtures of lignocellulosic biomass. Maximum laccase activity of Trametes gibbosa An 360, Vanderbylia fraxinea An 369, Perenniporia pyricola Han 202, Coriolopsis trogii Han 474, and Trametes versicolor Han 1504 was 55.83 ± 0.28 U/L on the mixture of corncob and cottonseed hull, 77.96 ± 1.60 U/L on corncob, 443.33 ± 15.49 U/L on corncob, 686.57 ± 16.49 U/L on corncob, and 162.04 ± 11.33 U/L on cottonseed hull. The mixed lignocellulosic material effectively improved the laccase activity of T. gibbosa An 360 compared with other fungal strains. However, the presence of corncob contributed to the secretion of laccase activity for V. fraxinea An 369, P. pyricola Han 202, and C. trogii Han 474. Meanwhile, cottonseed hull was conducive to the secretion of laccase of T. versicolor Han 1504. Laccase activity of P. pyricola Han 202 was very stable throughout most of the fermentation time. The results from this study provide new methods and increase fungal strains to improve laccase activity.

Laccase activity secreted by Pleurotus eryngii Han 1787 and Lentinus edodes Han 1788 grown on six types of agroindustrial wastes was investigated. Maximum laccase activity of P. eryngii Han 1787 on Ulmus pumila, Juniperus formosana, Pinus tabuliformis, cottonseed shell, corncob, and leaf of corncob was nearly 5.77-fold, 2.37-fold, 2.78-fold, 2.81-fold, 11.53-fold, and 6.73-fold higher than that of L. edodes Han1788 on corresponding agroindustrial wastes. In general, the capacity of secreting laccase of P. eryngii Han 1787 was superior to that of L. edodes Han 1788. Furthermore, laccase activity of P. eryngii Han 1787 on the leaf of corncob, the corncob, Ulmus pumila, and Juniperus formosana was relatively stable during the whole fermentation process. Different fungi showed different preferences in different agroindustrial wastes to secret laccase on whole fermentation stage. The presence of leaf of corncob was useful for improving laccase activity of P. eryngii Han 1787, while L. edodes Han 1788 was more preferred to produce laccase along with the presence of Juniperus formosana. These results were preliminary conducive in laying the foundation for increasing industrial laccase-producing strains and producing low-cost laccase.

The extensive application of laccase in various fields depends on the supply of a large amount of laccase with high activity and low cost. Interest on the screening of fungal strains suitable for obtaining massive high-activity laccase in solid-state fermentation with suitable low-cost lignocellulosic wastes has increased. The present work determined the laccase secretion from different species belonging to genera Ganoderma and Coriolopsis fermented on different lignocellulosic wastes. Maximal laccase activity was obtained from Ganoderma lingzhi Han 1345 grown on rice straw for 9 days and indicated the capacity of secreting laccase of G. lingzhi Han 1345 was superior to that of Coriolopsis trogii Han 1211, C. strumosa Han 1356, and G. applanatum Han 1578. The presence of cottonseed hull was more favorable for Coriolopsis species secreting laccase, while Ganoderma species were more preferred to secrete laccase on rice straw. Further, the consistent substrate preference in laccase production of different species in the same genus was first exhibited. The results are useful to screen and obtain new species with superior capacity of secreting laccase and suitable low-cost lignocellulosic wastes as fermentation substrate for further industrial application of laccase.

The laccase activity of three cultivated Pleurotus strains was investigated using different lignocellulosic biomasses for solid-state fermentation. The lignocellulosic biomasses were Sophora japonica, Salix babylonica, Populus beijingensis, and Pinus tabuliformis, which were selected because of their laccase producing ability and low cost. The maximum laccase activities from P. ostreatus Han 1189, P. citrinopileatus Han 1192, and P. eryngii Han 1205 using Sophora japonica were 768.74 U/L ± 11.25 U/L, 144.77 U/L ± 9.70 U/L, and 200.42 U/L ± 6.85 U/L, respectively. The three species of Pleurotus showed consistency in having a preference of hardwood to secret laccase under solid-state fermentation when facing hardwood and softwood as substrates. Furthermore, the presence of Sophora japonica was beneficial to improving the laccase activity for three Pleurotus strains. The capacity of the laccase secretion of P. ostreatus Han 1189 was superior to the capacity of P. citrinopileatus Han 1192 and P. eryngii Han 1205. The discovery was helpful for obtaining new high-producing strains and suitable wood materials, as well as expanding these high-producing strains for industrial applications to obtain high laccase activity, high laccase yield, and low cost laccase.

Laccase has huge potential application in all aspects of biotechnology due to the ability of laccase to oxidize a wide range of phenolic and non-phenolic compounds. The future success of such applications requires large amounts of laccase with low costs. White-rot fungi are important groups of laccase production. In this study, three white-rot fungi, Phlebia acerina Han 618, Trametes hirsuta Han 726, and Coriolopsis trogii Han 751, isolated from a native North China habitat, were identified by the method of molecular biology and preliminary screening of the ability of laccase-production by guaiacol selection medium. Then they were fermented on different lignocellulosic biomass. Three species showed consistency in preference of lignocellulosic biomass, and the presence of stalk of Sorghum bicolor was more suitable for secreting laccase. The capacity of laccase secretion from different species was significantly different. The capacity of secreting laccase of C. trogii Han 751 was superior to that of P. acerina Han 618 and T. hirsuta Han 726. The discovery of a new strain with superior capacity of secreting laccase and suitable lignocellulosic biomass were helpful for laying a foundation for the optimization of the fermentation conditions for the highest laccase production, the isolation and purification of laccase, and the industrial application of laccase.

Laccase activity from Pleurotus ostreatus and Flammulina velutipes strains was investigated with various agro- and forestry residues by solid-state fermentation. Different species or strains belonging to the same species had the unique capacity of secreting laccase on solid-state fermentation with various agro- and forestry residues. Overall, the capacity of secreting laccase for P. ostreatus strains was superior to F. velutipes strains due to the value of maximum activity on various agro- and forestry residues, except on the stalk of straw. Compared with Populus beijingensis, corncob, and stalk of straw, the presence of cottonseed hull was helpful to improve laccase activity for P. ostreatus strains because the maximum laccase activity from cottonseed hull was higher than that from the other three agro- and forestry residues. The presence of stalk of straw was more helpful to improve laccase activity for F. velutipes strains because of the maximum laccase activity from stalk of straw was higher that from Populus beijingensis, corncob, and cottonseed hull. These results indicated the importance of selecting suitable agro- and forestry residues for fungi producing laccase. These findings contributed to the selection of suitable strains to obtain an integrated application of low-cost laccase in the factory.

The capacity of novel isolated white-rot fungi secreting laccase was evaluated for various kinds of lignocellulosic biomass in submerged fermentation. The laccase secreted by Neofomitella fumosipora Han 386 and Pleurotus pulmonarius Han 527 was significantly faster than that by Coriolopsis trogii Han 751 and Coriolopsis sanguinaria An 282. Maximum laccase from N. fumosipora Han 386 on the four kinds of lignocellulosic biomass tested appeared on the first day. This phenomenon indicated that N. fumosipora Han 386 secreted laccase rapidly compared with other tested strains in this study and showed the superiority in the rate of secreting laccase. Based on the maximum laccase activity, the ability of secreting laccase of C. sanguinaria An 282 was superior to other tested novel isolated strains. On the whole, N. fumosipora Han 386 and P. pulmonarius Han 527 preferred Toona sinensis to produce laccase, C. trogii Han 751 preferred to produce laccase on Populus beijingensis, and C. sanguinaria An 282 grown on Sorghum straw was more suitable for secreting laccase. The results will be helpful for developing bioprocesses using various kinds of lignocellulosic biomass for lignocellulolytic enzyme production and enlarging the number of laccase producing strains for industrial application.

Pleurotus ostreatus and a newly isolated Ganoderma lingzhi strain were evaluated for their laccase secretion capacity by solid-state fermentation with different agricultural and forestry residues. There was a significant difference among fungi for biosynthetic potential. In principle, the laccase secretion capacity of P. ostreatus CY 568 was stronger than that from G. lingzhi Han 500. Different species of fungi had a preference for agricultural and forestry residues. The presence of cottonseed hull and Populus beijingensis were helpful for accelerating the rate of laccase enzyme production of P. ostreatus CY 568. Cottonseed hull and corncob were useful for improving the production of laccase from G. lingzhi Han 500. Continuous and stable laccase production was found on cottonseed hull by P. ostreatus CY 568 and G. lingzhi Han 500. Maximum laccase activity obtained from P. ostreatus CY 568 on Toona sinensis, Sophora japonica, Salix babylonica, Populus beijingensis, corncob, cottonseed hull, and straw of Oryza sativa was higher than that from G. lingzhi Han 500, and was nearly 1.16-fold, 1.59-fold, 3.32-fold, 1.39-fold, 1.08-fold, 1.08-fold, and 1.36-fold, respectively. These findings will be helpful for developing new productive strains and expanding more species for industrial application to obtain efficient and low-cost laccase.

The laccase producing abilities of four Basidiomycete fungi species were compared using solid-state fermentation using four different lignocellulosic residues. The biosynthetic potential of the Basidiomycetes was highly dependent on the type of fungi. In general, the laccase secreting ability of Cerrena unicolor Han 849 was greater than Lenzites betulinus Han 851, Stropharia rugosoannulata Han 1321, and Auricularia heimuer Han 1333. The maximum laccase production of C. unicolor Han 849 was approximately 11.25, 122.26, and 15.27 times higher than L. betulinus Han 851, S. rugosoannulata Han 1321 and A. heimuer Han 1333, respectively. Different species of fungi had a preference in lignocellulosic residues. The presence of Firmiana platanifolia was conducive to secreting laccase via C. unicolor Han 849 during solid-state fermentation. A continuous and stable laccase production via C. unicolor Han 849 was an obvious advantage of solid-state fermentation with any of the four lignocellulosic residues used. The maximum laccase production of C. unicolor Han 849 using Firmiana platanifolia was approximately 2.12, 1.68, and 6.13 times higher than Populus beijingensis, Sorghum bicolor, and Oryza sativa, respectively. These findings will be helpful for developing new productivity strains in industrial applications and selecting suitable lignocellulosic residues for laccase production.

Different Pleurotus ostreatus and Flammulina velutipes species were compared relative to their ability to produce laccase in submerged fermentation of various lignocellulosic wastes. Fungi cultivation in identical culture conditions revealed wide differences among both species and strains of the same species. The laccase secretion ability of P. ostreatus strains was superior to F. velutipes strains. Maximum laccase production on cottonseed hull, corncob, and poplar wood was secreted by P. ostreatus CY 568, P. ostreatus CCEF 89, and P. ostreatus CY 568, respectively. The nature of lignocellulosic materials played an important role in determining the expression of laccase potential of fungi. The presence of cottonseed hull improved laccase activity and accelerated the rate of enzyme production. Maximum laccase production on cottonseed hull was nearly 1.29-fold and 1.53-fold higher than that on corncob and poplar wood, respectively. Laccase activity was detected in almost all tested strains on cottonseed hull on the first day, while only a few strains on poplar wood and corncob were detected on the first day. These findings will be helpful for selecting the appropriate strain in industrial applications and for optimization of integrated industrial laccase production.

Solid state fermentation with different lignocellulolytic materials as inducers was used for lignocellulolytic enzyme production in this study. Pleurotus ostreatus strains were assessed by measuring laccase, CMCase, and xylanase activities. The secretion potential of the lignocellulolytic enzymes by wild and cultivated strains was analyzed for the first time. The wild and cultivated strain showed their unique capacities for secreting lignocellulolytic enzymes on solid-state fermentation with different lignocellulosic materials. The wild P. ostreatus strain preferred corncob for the secretion of laccase and xylanase activity, but the cultivated strain preferred poplar sawdust. The wild strain and cultivated strain showed a consistent preference for poplar sawdust for the secretion of CMCase activity. The wild strain was advantageous because it achieved the maximum hydrolytic enzyme activities within a short time period. Poplar sawdust and corncob were conducive to laccase secretion by the wild or cultivated strains and the rapid accumulation of laccase on solid-state fermentation. Additionally, continuous, stable laccase production was an extremely important advantage by solid-state fermentation of poplar sawdust, particularly in the wild strain. These findings are helpful in selecting the appropriate strain that corresponds to suitable lignocellulosic materials. The optimization of integrated industrial lignocellulolytic enzyme production can also be achieved.

Sequential submerged cultivation with different induction media as inducers of ligninolytic enzyme production by Pleurotus ostreatus strains was assessed by measuring laccase activities. An unconventional material, alkali lignin, was used for the first time as an inducer for different strains to enhance laccase activity. The P. ostreatus strains secreted similar but relatively high levels of laccase activity when the induction media contained alkali lignin with or without glucose. The laccase enzyme of different P. ostreatus strains in the different media exhibited large differences, and the wild strain YAASM 0568 exhibited enhanced production of laccase compared to other cultivated strains. The laccase activities of wild strain YAASM 0568 were nearly 3.4-, 3.3-, and 5.4-fold higher than that for cultivated strains CCMSSC 00322, CCMSSC 00406, and CCMSSC 00336, respectively, when the induction media contained alkali lignin, inorganic salt, and vitamin B1. In general, induction media containing alkali lignin with or without glucose were favorable for laccase secretion. The results revealed that the type of induction material and the nature of the fungus play important roles in the expression of ligninolytic enzymes. These findings would be helpful for selection of the appropriate type of strain and for optimization of integrated industrial ligninolytic enzyme production.

Sequential solid-state and submerged cultivation with various lignocellulosic biomasses as a substrate for lignocellulolytic enzyme production by Pleurotus ostreatus were assessed by measuring endoglucanase, xylanase, and laccase activities. An unconventional pre-culture method was established by cultivating the P. ostreatus mycelia in a solid substrate medium for an initial fungal growth phase, followed by a transition to submerged fermentation through adding a liquid culture medium. The lignocellulolytic enzymes of P. ostreatus in different fermentation methods revealed wide differences. The higher yields of endoglucanase (3152 ± 139 U/L), xylanase (3064 ± 40 U/L), and laccase (543 ± 21 U/L) were achieved by using the sequential solid-state submerged method compared to conventional solid-state and submerged cultivation. Generally speaking, sequential solid-state and submerged fermentation of cottonseed hull is favorable for laccase secretion, whereas sequential solid-state and submerged fermentation of corncob provides better production of hydrolytic enzymes. These results revealed that the nature of the lignocellulosic biomass and the fermentation method play an important role in the expression of lignocellulolytic enzymes. This indication would be helpful in optimizing the production of integrated industrial lignocellulolytic enzymes.