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A successful conversion of lignocellulosic biomass into biofuel could be achieved through an ionic liquids (ILs)-pretreatment and an enzyme saccharification. In this study, the fungal strains with high cellulase productions were isolated and identified as Penicillium janthinellum FHH1 and P. oxalicum FLY4. A high cellulase production was obtained at pH 4.0 and 30 °C for P. janthinellum FHH1 with corn stalk and beef extract for 9 days and for P. janthinellum FHH1 with corn stalk and peptone for 7 days. A pH range between 4.0 to 6.0 and a temperature range from 55 °C to 60 °C were applicable for cellulase with high activities during hydrolysis. A high NaCl-stability and a relatively high ILs-stability were found for cellulase obtained from P. oxalicum FLY4. High yields of reducing sugar were obtained by enzymatic hydrolysis of the original corn stalk and ILs-pretreated corn stalk. P. oxalicum FLY4 has a great potential for ILs-assisted fungi in the degradation of lignocellulosic biomass into value-added products.

Indole-3-acetic acid (IAA) plays an important role in the growth and development of plants. In this study, a series of predominant strains were isolated and identified as Enterobacter sp. with remarkable IAA-producing capabilities. The IAA-producing strains are mainly tryptophan-dependent and have significantly high yields of IAA (3477 μg mL−1 and 3378 μg mL−1). The ipdC gene encoding indole-3-pyruvate decarboxylase was identified by genomic analysis and RT-qPCR analysis, indicating the involvement of the indole-3-pyruvic acid (IPyA) pathway of IAA biosynthesis. The IPyA pathway was also confirmed by the intermediate assay. The IAA product of microbial metabolites was isolated, purified and characterized. These microbes exhibiting IAA production significantly promoted the growth of maize, increasing root length, plant height, fresh weight and dry weight. Thus, Enterobacter sp. with high IAA production has great prospects in agricultural and industrial applications.

Ionic liquids (ILs) are effective solvents for lignocellulose pretreatment. Enzymatic saccharification converts pretreated lignocelluloses into valuable products, and IL-tolerant cellulase improves the enzymatic efficiency and the reuse of ILs. In this study, a fungal strain with a relatively high cellulase production was isolated and identified as Aspergillus aculeatus G1-3. The high production of β-glucosidase (1.943 U per mL), CMCase (1.303 U per mL), and FPase (0.165 U per mL) was obtained using corn stover as the carbon source and peptone as the nitrogen source. The results were obtained at pH 8.0 and 30 °C with an inoculation size of 3% (volume per volume) for 7 days. A mutant strain Aspergillus aculeatus P6 with β-glucosidase (7.023 U per mL), CMCase (1.543 U per mL), and FPase (0.098 U per mL) was obtained by 60Co-γ irradiation. The cellulase activity was measured at pH 5.0 and 60 °C for enzymatic hydrolysis. The cellulase from mutant strains was stable in different concentrations of 1-ethyl-3-methylimidazolium acetate. Enzymatic saccharification of the original corn stover and ILs-pretreated corn stover was successfully performed with high sugar yields. The mutant strains of Aspergillus aculeatus have great potential for their further application in the conversion of lignocellulosic biomass into biofuels.

Phosphate-solubilizing microorganisms have been considered as a novel alternative approach to provide phosphate fertilizers that promote plant growth. In this study, three strains were isolated and identified as Penicillium oxalicum FJG21, Penicillium oxalicum FJQ5, and Bacillus subtilis BPM12, with a relatively high phosphate-solubilizing activity. Various phosphate sources were investigated, and Ca3(PO4)2 was identified as the effective phosphate source. Factors governing the phosphate-solubilizing activity of the strains included carbon and nitrogen sources, initial pH, and fermentation time. A high soluble phosphorus content was achieved with 529.0 μg·mL-1, 514.0 μg·mL-1, and 330.7 μg·mL-1 for Penicillium oxalicum FJG21, Penicillium oxalicum FJQ5, and Bacillus subtilis BPM12, respectively. An inverse correlation of the quantity of soluble phosphorus content and the pH value of the medium was observed. In addition, Bacillus subtilis BPM12 displayed a prominent capability of producing indole acetic acid. Penicillium oxalicum FJG21 and Penicillium oxalicum FJQ5 exhibited high cellulase activities. These phosphate-solubilizing microorganisms with good phosphate-solubilizing capability and growth-promoting ability are the promising strains for agricultural utilization.

Mono-cationic ionic liquids (MILs) have been widely utilized for the treatment of lignocelluloses. However, the hydrophilic property of MILs increases the difficulty of isolating sugars and their reuse, which limits their industrial application. In the present study, a series of dicationic ionic liquids (DILs) were synthesized with totally different di-cations and di-anions. An alternating miscibility of DILs with water was observed depending on the dealing temperature. The functional DILs exhibiting hydrophobic and acidic properties were investigated for the treatment of corn stalk. High yields of sugars were achieved as 27.8% and 31.6% with DIL3 and DIL4, respectively. Cellulosic materials were obtained as 74.3% and 77.8% with DIL1 and DIL2 and 61.2% and 65.7% with DIL3 and DIL4, respectively. Enzymatic reaction was successfully performed with cellulosic materials after the DIL treatment. DILs were recycled and reused with no significant reduction in sugar yields. Hydrophobic DILs are a potentially effective approach to enable the successful decomposition and degradation of lignocellulosic biomass.

Indole-3-acetic acid (IAA) plays an important role in the growth and development of plants. In this study, a series of predominant strains were isolated and identified as

There is increasing interest in the application of ionic liquids for the pretreatment and fractionation of lignocelluloses. In this study, a series of functional acidic ionic liquids (ILs) with various heterocyclic organic cations were synthesized. Corn stalks were successfully fractionated into lignin, hemicelluloses, and cellulose when ultrasonically pretreated with ILs at 70 °C for 3 h, and subsequently treated with alkaline extraction. High yields of IL-isolated lignin (18.3% to 19.6%) and (8.3% to 14.6%) were obtained using ILs in the absence and presence of water, respectively. The yield of cellulose ranged from 40.0 to 77.0% from IL treatments, whereas the yield of hemicelluloses ranged from 1.1% to 17.3%. Enzymatic hydrolysis of the isolated cellulose residual produced 89.2% to 94.9% reducing sugar with 77.8% to 86.1% glucose, which corresponded to 80.5% to 91.4% enzymatic conversion of cellulose. Syringol and vanillin were found as the main lignin degradation products.

Background: Indole-3-acetic acid (IAA) plays an important role in the growth and development of plants. Various bacteria in the rhizosphere are capable to produce IAA that acts as a signaling molecule for the communication between plants and microbes to promote the plant growth. Due to the low IAA content and various interfering analogs, it is difficult to detect and isolate IAA from microbial secondary metabolites. Results: A predominant strain with a remarkable capability to secrete IAA was identified as Enterobacter xiangfangensis BHW6 based on 16S rRNA gene sequence, the determination of average nucleotide identity (ANI) and digital DDH (dDDH). The maximum IAA content (134-1129 μg/mL) was found with the addition of 0.2-15 g/L of L-tryptophan at pH 5 for 6 days, which was 4-40 fold higher than that in the absence of L-tryptophan. The highest yield of IAA was obtained at the stationary phase of bacterial growth. An acidic culture medium was preferred for the IAA biosynthesis of the strain. The strain was tolerant and stable to produce IAA in the presence 2.5%-5% (w/v) of NaCl. IAA was then isolated through column chromatography with a mobile phase of hexane/ethyl acetate (1/2, v/v) and characterized by 1H Nuclear Magnetic Resonance (1H NMR). Conclusions: A remarkable IAA production was obtained from E. xiangfangensis BHW6 that was tryptophan–dependent. According to genomic analysis, the ipdC gene coding for the key enzyme (indole-3-pyruvate decarboxylase) was identified indicating that IAA biosynthesis was mainly through the indole-3-pyruvia acid (IPyA) pathway, which was further confirmed by intermediate assay. E. xiangfangensis BHW6 with an important economic value has great prospect in agricultural and industrial application.

Lignocellulosic biomass as one of the most abundant and renewable resources has great potential for biofuel production. The complete conversion of biomass to biofuel is achieved through the effective pretreatment process and the following enzyme saccharification. Ionic liquids (ILs) are considered as a green solvent for lignocellulose pretreatment. However, ILs exhibit an inhibitory effect on cellulase activity, leading to a subsequent decrease in the efficiency of saccharification. The screening of new potential IL-tolerant cellulases is important. In the current study, a fungal strain with a relatively high cellulase production was isolated and identified as Penicillium oxalicum HC6. The culture conditions were optimized using corn stover and peptone as the carbon source and nitrogen source at pH 4.0 and 30 °C with an inoculation size of 2% (v/v) for 8 days. It was found that P. oxalicum HC6 exhibited potential salt tolerance with the increase of the enzyme production at a salt concentration of 5.0% (w/v). In addition, high enzyme activities were obtained at pH 4.0–6.0 and 50–65 °C. The crude enzyme from P. oxalicum HC6 with good thermal stability was also stable in the presence of salt and ILs. Good yields of reducing sugar were obtained by the crude enzyme from P. oxalicum HC6 after the saccharification of corn stover that was pretreated by ILs. P. oxalicum HC6 with potentially salt-tolerant and IL-tolerant enzymes has great potential application in the enzymatic saccharification of lignocellulose.

Ionic liquid (IL)-assisted pretreatment of lignocellulosic biomass has been extensively studied. Cellulose and hemicelluloses are rich resources of sugars for biofuels. Lignin is a valuable feedstock for aromatic-based platform chemicals. In this study, a series of ionic liquids (ILs) were prepared with one-step synthesis and were investigated for their activity to pretreat lignocelluloses. High yields of lignin (61.0% and 60.4%) were achieved through [Hpy]Cl and [Hmim]Cl pretreatment of poplar. Lignin yields of 51.7% and 50.3% were obtained with a [Hpy]Cl and [Hnmp]Cl pretreatment of bamboo. Improving enzymatic hydrolysis was observed from the regenerated poplar with [Hpy]Cl pretreatment and the regenerated bamboo with [Hmim]Cl pretreatment. The isolated fractions were characterized by FTIR (Fourier transform infrared) spectroscopy. SEM (Scanning electron microscopy) and XRD (X-ray diffractometry) were employed to examine the cellulose-rich materials. A 2D 1H–13C heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy was employed to analyze lignin fraction. These ionic liquids were particularly effective to extract lignin from lignocelluloses to obtain cellulose-rich materials for biofuels.

A series of dicationic ionic liquids (ILs) including [PF6][(PYR)C4(MIM)][Cl], [PF6][(PYR)C4(PYR)][Cl], [PF6][(PYR)C5(MIM)][Cl], and [PF6][(PYR)C5(PYR)][Cl], and monocationic ILs including [(PYR)C4Cl][PF6], [(PYR)C5Cl][PF6], [(MIM)C2COOH][PF6] and [(PYR)C2COOH][PF6] were synthesized. Their thermal stability and melting points were determined. Their solubility with organic solvents and the miscibility with water were investigated. These functional ILs are hydrophilic at high temperatures and they are hydrophobic at low temperatures, which enable the effective isolation of the resulting reducing sugar. High yields of reducing sugar were obtained for corn stalk after 8 h (20.73%) and potato starch after 6 h (72.50%) by the treatment with the mixture of [PF6][(PYR)C4(PYR)][Cl] and [(PYR)C2COOH][PF6]. The reuse of dicationic and monocationic ILs was successfully performed and no significant reduction in yields of reducing sugar was observed. These functional ILs have important implications in the design of homogeneous and heterogeneous systems with water and organic solvents, which could be used to satisfy some specific applications.

Ionic liquid (IL)-assisted pretreatment is an important step in biochemical conversion of lignocellulosic biomass into biofuels. Design for low-cost ILs that efficiently work at a relatively low pretreatment temperature with a short processing time is of great interest. In this work, a functional acidic ionic liquid, 1-H-N-methyl-2-pyrrolidonium chloride ([Hnmp]Cl), was prepared by a simple synthetic procedure in a cost-effective manner and was then investigated for use in the pretreatment of lignocellulosic biomass. Factors including temperature, time, ratio of biomass to ionic liquid, and water content were studied to determine their impact on the pretreatment of lignocellulose; 91.39% of lignin content was recovered when the corn stalk was pretreated by pure [Hnmp]Cl at 100 °C for 45 min with a biomass loading of 5%. The highest glucose yield attained was 93.20% and the highest cellobiose yield was 18.76%, when the ratio of biomass to water was kept at 1:4. The pretreatment efficacy was dependent on the pretreatment temperature and processing time, which was more efficient for pure ionic liquid with respect to lignin recovery from lignocelluloses. However, more efficient enzymatic saccharification of cellulose-rich materials was achieved with aqueous ionic liquid.

Lignocellulosic biomass as a renewable and valuable resource has been a very active research area during recent years. Ionic liquids (ILs) are an attractive approach for the pretreatment of lignocelluloses. In this work, a series of pyrrolidinium-based ionic liquids were prepared simply and were investigated for the pretreatment of corn stalk at 90 °C for 30 min. The characteristics of regenerated lignin and cellulose-rich materials were determined by Fourier transform infrared spectroscopy (FTIR) analysis. Both ILs and ILs/H2O were studied. Notably, 10.17% lignin based on the original corn stalk was recovered with [Hmp]Cl-pretreatment; 21.34% and 15.83% reducing sugar based on the original corn stalk were observed during pretreatment with [Hmp]HSO4/H2O and [Hmp]Cl/H2O pretreatment, respectively; 80.54% of reducing sugar was obtained based on the cellulose-rich materials with [Hmp]Cl/H2O-pretreatment. Also, the glucose and cellobiose yields were 73.82% and 8.64%, respectively.

A series of dicationic ionic liquids (ILs) including [C 4 (MIM) 2 ][PF 6 ] 2 , [C 5 (MIM) 2 ][PF 6 ] 2 , [C 6 (MIM) 2 ][PF 6 ] 2 and [C 4 (PYR) 2 ][PF 6 ] 2 were synthesized. Their thermal stability and melting points were analysed. It was found that dicationic ILs presented important implications in the design of homogeneous and heterogeneous system with water. A homogeneous system of dicationic ILs with water could be formed at a relatively high temperature and then a heterogeneous system was formed when the solution was cooled to a low temperature. The ILs recovered by altering the temperature were obtained in high percentage yields of [C 4 (MIM) 2 ][PF 6 ] 2 (97.6%), [C 5 (MIM) 2 ][PF 6 ] 2 (97.3%), [C 6 (MIM) 2 ][PF 6 ] 2 (98.0%) and [C 4 (PYR) 2 ][PF 6 ] 2 (94.2%). On the other hand, [C 4 (MIM) 2 ][PF 6 ] 2 and [C 5 (MIM) 2 ][PF 6 ] 2 exhibited good solubility in acetonitrile and acetone. A homogeneous system could be achieved with imidazolium-based ILs with a relatively low amount of water and acetonitrile at room temperature. All of the properties of dicationic ILs have a strong correlation with the nature of dications, the linkage chain and the symmetry of dications. Dicationic ILs may provide a new opportunity for some specific applications in order to enable the effective separation and isolation of products.

Lignocellulosic biomass is increasingly being promoted as an environmentally and economically sustainable fuel. However, the complex structure of lignocellulose makes it difficult to be fractionated, which limits its conversion into valuable products. In this work, a series of functional acidic ionic liquids (ILs) with a simple synthetic procedure were prepared. Fractionation of corn stover into cellulose, hemicellulose and lignin was successfully performed in ultrasound-assisted ILs at a low reaction temperature of 70 °C for 3 h followed by alkaline extraction. IL-isolated lignin, alkaline lignin, hemicellulose and cellulose were obtained in good yields and their chemical properties were analyzed by FTIR. Significantly, a good yield of IL-isolated lignin was obtained, which accounted for 60.48% of the original lignin. The IL-isolated lignin was S-G-H type indicating by 13C NMR and 13C–1H correlation 2D NMR (HSQC) analysis. Enzymatic hydrolysis of cellulose was performed successfully. A high yield of 97.77% reducing sugar was achieved. Glucose and cellobiose were measured by HPLC analysis, which accounted for 92.55% of cellulose conversion. Both of the hydrogen bond capability and the acidity of ILs contributed to achieve the effective fractionation. These ILs have a great potential for the preparation of biofuel.

Ionic liquids (ILs) as “green solvents” provided an effective and efficient procedure for Knoevenagel condensation reactions. It is applicable for a large range of aldehydes, ketones with active methylene compounds. ILs can significantly promote the reaction rates. High yields and selectivity of products have been observed. ILs can be recycled and reused. In this paper, the recent achievements of Knoevenagel condensation reactions promoted by ILs are reviewed.

Like bacteria, fungi play an important role in the composting process as major decomposers of organic substances. As only a small fraction of the fungi present in composting can be cultured because conventional microbiological techniques limited information on the composition of fungal communities in composting. Molecular methods are expected to give a more realistic view of species richness and distribution. For this purpose, we selected universal PCR primer set that allow the specific amplification of fungal 18S-ribosomal-DNA (rDNA) sequences. DNA was extracted from composting samples, and 18S rDNA genes were amplified by EF4/Fung5 (0.6kb) and EF4/NS2-GC (0.4kb). DGGE analysis of the fungal community in the composting of a microcosm experiment was carried out after amplification of total DNA with both primer pairs. Clear banding patterns were obtained with amplified production. 13 different bands excised from the DGGE gel were sequenced and compared with genbank. Sequencing showed that some could not be cultured; some were efficient cellulose-degrading strains. The results showed that diversity and composition of the fungal community in the composting can be analyzed by the combination of 18S rDNA PCR amplification and DGGE.

Ionic liquids (ILs) as “green solvents” provided an effective and efficient procedure for Knoevenagel condensation reactions. It is applicable for a large range of aldehydes, ketones with active methylene compounds. ILs can significantly promote the reaction rates. High yields and selectivity of products have been observed. ILs can be recycled and reused. In this paper, the recent achievements of Knoevenagel condensation reactions promoted by ILs are reviewed.

In this paper, the shifts of 5DJ and 7FJ energy levels of Eu3+ ion caused by crystal field effect, are calculated in 25 hosts containing Eu3+ ions. The relation between the calculated shifts and experimental values are analysed. The correct order on nephelauxetic effect shifts in these hosts is given.