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Wang X.,University of South China | Wang X.,Key Laboratory of Biomass Energy of Guangdong Regular Higher Education Institutions | Wang X.,Key Laboratory of Energy Plants Resource and Utilization | Chen D.,University of South China | And 8 more authors.
PLoS ONE | Year: 2015

The plant Dioscorea composita has important applications in the medical and energy industries, and can be used for the extraction of steroidal sapogenins (important raw materials for the synthesis of steroidal drugs) and bioethanol production. However, little is known at the genetic level about how sapogenins are biosynthesized in this plant. Using Illumina deep sequencing, 62,341 unigenes were obtained by assembling its transcriptome, and 27,720 unigenes were annotated. Of these, 8,022 unigenes were mapped to 243 specific pathways, and 531 unigenes were identified to be involved in 24 secondary metabolic pathways. 35 enzymes, which were encoded by 79 unigenes, were related to the biosynthesis of steroidal sapogenins in this transcriptome database, covering almost all the nodes in the steroidal pathway. The results of real-time PCR experiments on ten related transcripts (HMGR, MK, SQLE, FPPS, DXS, CAS, HMED, CYP51, DHCR7, and DHCR24) indicated that sapogenins were mainly biosynthesized by the mevalonate pathway. The expression of these ten transcripts in the tuber and leaves was found to be much higher than in the stem. Also, expression in the shoots was low. The nucleotide and protein sequences and conserved domains of four related genes (HMGR, CAS, SQS, and SMT1 ) were highly conserved between D. composita and D. zingiberensis; but expression of these four genes is greater in D. composita. However, there is no expression of these key enzymes in potato and no steroidal sapogenins are synthesized. © 2015 Wang et al.


Xu X.,University of South China | Xu X.,Key Laboratory of Energy Plants Resource and Utilization | Feng L.,University of South China | Han Z.,Key Laboratory of Energy Plants Resource and Utilization | And 4 more authors.
Journal of Microbiology and Biotechnology | Year: 2016

Commercial application of laccase is often hampered by insufficient enzyme stocks, with very low yields obtained from natural sources. This study aimed to improve laccase production by mutation of a Coriolopsis gallica strain and to determine the biological properties of the mutant. The high-yield laccase strain C. gallica TCK was treated with N-methyl-N-nitro-Nnitrosoguanidine and ultraviolet light. Among the mutants isolated, T906 was found to be a high-production strain of laccases. The mutant strain T906 was stabilized via dozens of passages, and the selected ones were further processed for optimization of metallic ion, inducers, and nutritional requirements, which resulted in the optimized liquid fermentation medium MF9. The incubation temperature and pH were optimized to be 30°C and 4.5, respectively. The mutant strain T906 showed 3-times higher laccase activity than the original strain TCK under optimized conditions, and the maximum laccase production (303 U/ml) was accomplished after 13 days. The extracellular laccase isoenzyme 1 was purified and characterized from the two strains, respectively, and their cDNA sequence was determined. Of note, the laccase isoenzyme 1 transcription levels were overtly increased in T906 mycelia compared with values obtained for strain TCK. These findings provide a basis for C. gallica modification for the production of high laccase amounts. © 2016 by The Korean Society for Microbiology and Biotechnology.


PubMed | Key Laboratory of Energy Plants Resource and Utilization, Key Laboratory of Biomass Energy of Guangdong Regular Higher Education Institutions and University of South China
Type: Journal Article | Journal: Journal of microbiology and biotechnology | Year: 2016

Commercial application of laccase is often hampered by insufficient enzyme stocks, with very low yields obtained from natural sources. This study aimed to improve laccase production by mutation of a Coriolopsis gallica strain and to determine the biological properties of the mutant. The high-yield laccase strain C. gallica TCK was treated with N-methyl-N-nitro-N-nitrosoguanidine and ultraviolet light. Among the mutants isolated, T906 was found to be a high-production strain of laccases. The mutant strain T906 was stabilized via dozens of passages, and the selected ones were further processed for optimization of metallic ion, inducers, and nutritional requirements, which resulted in the optimized liquid fermentation medium MF9. The incubation temperature and pH were optimized to be 30C and 4.5, respectively. The mutant strain T906 showed 3-times higher laccase activity than the original strain TCK under optimized conditions, and the maximum laccase production (303 U/ml) was accomplished after 13 days. The extracellular laccase isoenzyme 1 was purified and characterized from the two strains, respectively, and their cDNA sequence was determined. Of note, the laccase isoenzyme 1 transcription levels were overtly increased in T906 mycelia compared with values obtained for strain TCK. These findings provide a basis for C. gallica modification for the production of high laccase amounts.


Ma L.,State Key Laboratory for Conservation and Utilization of Subtropical Agro bioresources | Rao X.,CAS South China Botanical Garden | Lu P.,Energy Resources of Australia Ltd | Bai S.H.,Griffith University | And 5 more authors.
Environmental Science and Pollution Research | Year: 2015

Eucalyptus spp. is a dominant tree genus in Australia and most Eucalyptus spp. are canopy dominant species. In Australian natural forests, Eucalyptus spp. commonly are associated with understorey legumes which play a crucial role for ecological restoration owing to their nitrogen (N) fixing ability for replenishing the soil N lost after frequent prescribed burning. This study aimed to explore to what extent physiological responses of these species differ 7 and 12 years after last fire. Two most common understorey Acacia spp., Acacia leiocalyx and A. disparrima, as well as one non-leguminous Eucalyptus resinifera, were studied due to their dominance in the forest. Both A. leiocalyx and A. disparrima showed higher carbon (C) assimilation capacity, maximum photosynthetic capacity, and moderate foliar C/N ratio compared with E. resinifera. A. leiocalyx showed various advantages compared to A. disparrima such as higher photosynthetic capacity, adaptation to wider light range and higher foliar total N (TNmass). A. leiocalyx also relied on N2-fixing ability for longer time compared to A. disparrima. The results suggested that the two Acacia spp. were more beneficial to C and N cycles for the post burning ecosystem than the non-N2-fixing species E. resinifera. A. leiocalyx had greater contribution to complementing soil N cycle long after burning compared to A. disparrima. © 2015, Springer-Verlag Berlin Heidelberg.


Ruan Z.-H.,Key Laboratory of Energy Plants Resource and Utilization | Ruan Z.-H.,South China Agricultural University | Wu J.-H.,South China University of Technology | Huang J.-F.,Key Laboratory of Energy Plants Resource and Utilization | And 14 more authors.
Journal of Materials Chemistry A | Year: 2015

Pure nanometals have poor adsorption capacity due to their agglomeration in aqueous solution. In this study, biochar (Bc) prepared by the pyrolysis of rosin and coated on bentonite (Bt) was designed to support and disperse nanoscale α-Fe2O3 (Bt/Bc/α-Fe2O3). The generation of α-Fe2O3 nanoparticles and the pyrolysis of rosin on the surface of Bt were accomplished in a one-step heating route. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the pyrolysis of rosin into biochar and the production of α-Fe2O3 in the composite. Besides, scanning electron microscopy (SEM) images showed good dispersion of α-Fe2O3 nanoparticles on the biochar surface. This adsorbent demonstrated fast Cr(vi) adsorption property with a Cr(vi) removal efficiency of 95% within one minute and high Cr(vi) adsorption capacity with a maximum Cr(vi) removal up to 81.7 mg g-1 based on the Langmuir model. The remarkable improvement of Cr(vi) adsorption on Bt/Bc/α-Fe2O3 was attributed to the good dispersion of α-Fe2O3 nanoparticles by the biochar network in comparison with other similar adsorbents. In addition, Bt/Bc/α-Fe2O3 maintained high Cr(vi) adsorption capacity under both acidic and basic conditions. This indicated that Bt/Bc/α-Fe2O3 can be used for fast Cr(vi) removal from wastewater or emergent Cr(vi) leakage due to its facile preparation and high efficiency in a wide range of pH. This journal is © The Royal Society of Chemistry 2015.


Shang C.,South China Agricultural University | Shang C.,Key Laboratory of Energy Plants Resource and Utilization | Shang C.,Key Laboratory of Biomass Energy of Guangdong Regular Higher Education Institutions | Shang C.,CAS Guangzhou Institute of Energy Conversion | And 10 more authors.
Journal of Applied Phycology | Year: 2016

Dunaliella parva can thrive and adapt to salt stress over a wide range of NaCl concentrations which also is related to carotenoid accumulation in Dunaliella. Dunaliella parva can accumulate carotenoids; however, the underlying mechanism of carotenoid accumulation needs further research. Thus, it is necessary to study biosynthesis and regulation of carotenoids for understanding carotenoid accumulation. In the present study, a gene encoding geranylgeranyl diphosphate synthase (GGPS) from the halophilic green alga D. parva has been cloned and analyzed. It is in the branch of terpene metabolism and named as DpGGPS (D. parva GGPS). The full-length complementary DNA (cDNA) of DpGGPS was 1612 bp, including an open reading frame (ORF) of 1059 bp, 189 bp 5′-untranslated region (5′-UTR) and 364 bp 3′-UTR. The 5′-flanking region was obtained by the genome walking method. Potential regulatory elements, associated with hormones, defense, and stress, were found in the 1310 bp 5′-flanking region. Functional characterization of DpGGPS in E. coli BL21(DE3) demonstrated that DpGGPS encoded a functional GGPS. Analysis of DpGGPS expression revealed a correlation between GGPS expression and the shift of NaCl concentration, which indicated that GGPS could be a salt stress responsive gene. Cloning and expression analysis of GGPS provides a foundation for studying the regulatory mechanism of carotenoid biosynthesis, adaptation mechanism to salt stress, and massive accumulation of carotenoids in D. parva. © 2016 Springer Science+Business Media Dordrecht

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