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Photoresponsive materials with high photoresponse sensitivity and photofatigue resistance are indispensable for applications, such as textiles and sensors fields. Herein, we synthesized photoresponsive polyamide 6 (PA6) with spiropyran (SP) as molecular component, by incorporating spiropyran-containing diisocyanate activator into anionic ring-opening polymerization of e-caprolactam. To improve photosensitivity and reduce response time, the corresponding nanofibrous membranes were obtained by electrospinning. The reversibility of the isomerization of SP resulted in colored nanofibrous membrane patterns, which can be written, erased, and rewritten, using UV light and visible light. It revealed that photosensitivity of nanofibrous membranes were further improved, when appropriate polyethylene glycol was covalently embedded into PA6 segments to increase the chain flexibility. Photoresponse reversibility and photofatigue resistance displayed that UV–vis absorbance intensity of SP-embedded PA6 nanofibrous membrane decreased just 13% after 10 cycles of UV light irradiation, while its absorbance intensity in UV–vis spectra after visible light irradiation has negligible decrease. For better understanding the structure, electronic characteristics and UV–vis absorbance peak of SP-embedded PA6, theoretical calculations were also carried out. Finally, UV absorption of transparent and flexible poly(dimethyl siloxane) (PDMS)/photoresponsive nanofibers composite film was assessed. The composite film was photochromic, and possessed excellent property for blocking ultraviolet radiation. This work explores a strategy for synthesizing photoresponsive SP-embedded polyamide 6 by incorporating spiropyran-containing activator into anionic ring-opening polymerization of e-caprolactam. SP-embedded PA6 nanofibrous membrane with excellent photosensitivity and photofatigue resistance was electrospun. The isomerization reversibility of spiropyran-merocyanine (SP-MC) resulted in colored patterns which can be written, erased, and rewritten using UV light and visible light. Transparent photochromic composite film for UV absorption and protection was also developed.

Silicon carbide particulate reinforced aluminum matrix composites (SiCp/Al) have received considerable attention in many engineering applications. However, the existence of dispersing SiC particles leads to particularly vulnerable edge quality of SiCp/Al composites in machining. It is very significant to improve the edge defects of SiCp/Al composites by optimizing the tool geometry. Cutting tool nose radius mainly determines the machining performance. Therefore, the effects of tool nose radius on the chip topography, cutting force, and edge geometry in face and dry milling of 20% SiCp/Al composites were investigated in the current work. Experiments were conducted with tool nose radius of 0.5, 1, 1.5, and 2 mm. The results showed that the shorter and wider chips were found with the increment in tool nose radius. It was also observed that the cutting force increased with the increment in tool nose radius. Based on the material removal mechanism with different tool nose radius, the feature maps of edge defects in SiCp/Al composites were established and studied. It was found that the outer and inner edge quality of the materials was improved with the increase of tool nose radius.

Lu Jing,1,2,* Liyan Hou,1,* Dongdong Zhang,1 Sheng Li,3 Zhengzheng Ruan,1 Xiaomeng Zhang,3 Jau-Shyong Hong,4 Qingshan Wang1,3 1Institute of Toxicology, School of Public Health, Dalian Medical University, Dalian, 116044, People’s Republic of China; 2Department of Neurology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, People’s Republic of China; 3National-Local Joint Engineering Research Center for Drug-Research and Development (R & D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, 116044, People’s Republic of China; 4Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA*These authors contributed equally to this workCorrespondence: Qingshan WangInstitute of Toxicology, School of Public Health, Dalian Medical University, No. 9 W. Lvshun South Road, Dalian, 116044, People’s Republic of ChinaTel +86 138 4081 7365Email wangq4@126.comBackground: Chronic exposure to the insecticide rotenone can damage dopaminergic neurons and lead to an increased risk of Parkinson’s disease (PD). Whereas it is not clear whether rotenone induces neurodegeneration of noradrenergic locus coeruleus (LC/NE) neurons. Chronic neuroinflammation mediated by microglia has been involved in the pathogenesis of PD. Evidence shows that complement receptor 3 (CR3) is a crucial regulator of microglial activation and related neurodegeneration. However, it is not clear whether CR3 mediates rotenone-elicited degeneration of LC/NE neurons through microglia-mediated neuroinflammation.Materials and Methods: Wild type (WT) and CR3 knockout (KO) mice were treated with rotenone. PLX3397 and minocycline were used to deplete or inactivate the microglia. Leukadherin-1 (LA-1) was used to modulate CR3. LC/NE neurodegeneration, microglial phenotype, and expression of CR3 were determined by using immunohistochemistry, Western blot and real-time polymerase chain reaction (PCR) techniques. The glutathione (GSH) and malondialdehyde (MDA) contents were measured by using commercial kits.Results: Rotenone exposure led to dose- and time-dependent LC/NE neuronal loss and microglial activation in mice. Depletion of microglia by PLX3397 or inhibition of microglial activation by minocycline significantly reduced rotenone-induced LC/NE neurodegeneration. Mechanistic studies revealed that CR3 played an essential role in the rotenone-induced activation of microglia and neurodegeneration of LC/NE neurons. Rotenone elevated the expression of CR3, and genetic ablation of CR3 markedly reduced rotenone-induced microglial activation and M1 polarization. LA-1 also suppressed rotenone-induced toxic microglial M1 activation. Furthermore, lack of CR3 or treatment with LA-1 reduced oxidative stress in the brainstem of rotenone-intoxicated mice. Finally, we found that mice deficient in CR3 or treated with LA-1 were more resistant to rotenone-induced LC/NE neurodegeneration than WT or vehicle-treated mice, respectively.Conclusion: Our results indicate that CR3-mediated microglial activation participates in rotenone-induced LC/NE neurodegeneration, providing novel insight into environmental toxin-induced neurotoxicity and related Parkinsonism.Keywords: pesticide, noradrenergic neuron, Parkinson’s disease, neuroinflammation, CR3, locus coeruleus

AIM 3-Phenyllactic acid (3-PLA) has been widely used in food and material industries. Three Lactobacillus crustorum strains have shown greater 3-PLA production ability in our previous study. The objectives of this study were to further improve 3-PLA yields in batch and continuous fermentation systems using of free-whole-cells of the three L. crustorum strains. MATERIALS AND RESULTS The fermentation conditions of free-whole-cells of the three L. crustorum strains for 3-PLA production were optimized. Among these strains, L. crustorum NWAFU 1078 showed excellent reusability and significantly (P

Silicon carbide particulate reinforced aluminum (SiCp/Al) matrix composites play an important role in aviation, aerospace, electronics, automobile, and other fields due to their outstanding mechanical properties. However, the existence of reinforcing SiC particles leads to poor cutting performance, terrible surface quality, and severe tool wear of SiCp/Al composites. In this study, a series of experiments were carried out with an ultrasonic vibration–assisted milling (UVAM) experimental device to study the effect of amplitude on the machinability of 20% SiCp/Al composites from four aspects: cutting force, surface roughness, surface morphology, and chip morphology. The results showed that it had a great influence on cutting force, surface roughness, surface morphology, and chips when the amplitude increased to 3 μm. The surface of workpiece material deteriorated rapidly and presented the fragmentation. In addition, a large number of micro-cracks and particle bulges appeared on the machined surface. It was suggested that the amplitude below 5 μm had a negative impact on the milling surface quality of 20% SiCp/Al composites, and the amplitude of 3 μm was considered as a critical value.

Polyunsaturated fatty acid (PUFA) synthase is a special and effective enzyme for PUFA synthesis, and dehydratase (DH) domain played a crucial role in it. In this work, we compared four different DH domains from different strains (Schizochytrium sp. HX-308 and Shewanella sp. BR-2) and different gene clusters. First bioinformatics analysis showed that DH1, 2 and DH3 were similar to FabA and PKS-DH, respectively, and all of them got a hot-dog structure. Second, four DH domains were expressed in Escherichia coli that increased biomass. Especially, Schi-DH1,2 presented the highest dry cell weight of 2.3 g/L which was 1.62 times of that of control. Fatty acids profile analysis showed that DH1,2 could enhance the percentage of unsaturated fatty acids, especially DH1,2 from Schizochytrium sp., while DH3 benefited for the saturated fatty acid biosynthesis. Furthermore, five kinds of fatty acids were added to the medium to study the substrate preferences. Results revealed that DH1,2 domain preferred to acting on C16:0, while DH3 domain trended acting on C14:0 and C15:0, which illustrated DH from different clusters do have specific substrate preference. Besides, DH expression could save the cell growth inhibition by mid-chain fatty acids. This study provided more information about the catalysis mechanism of polyunsaturated fatty acid synthase and might promote the modification study based on this enzyme.

SiC crystal has been widely used in semiconductor substrates because of its excellent physical, chemical, and photoelectric properties. As a semiconductor substrate, the SiC wafer not only needs good surface quality but also requires surface shape accuracy. In the present study, a novel lapping plate was designed for SiC wafers to improve their surface quality and shape accuracy. In the novel lapping plate, epoxy resin and a soft gel body containing diamond abrasives are combined to form a hard honeycomb structure. The cellular structure is used to support the lapping pressure to reduce the deformation of the lapping plate and improve the surface shape accuracy. The cellular structure is filled with soft gel with diamond abrasives which play the role of semifixed lapping to obtain good surface quality. Two crystalline forms of silicon carbide (4H-SiC and 6H-SiC) were selected to carry out double-sided lapping experiments with the novel lapping plate. The experimental results show that the lapped wafers have good surface quality with low surface roughness, some small scratches, and acceptable cracks. In addition, the surface shape accuracy is improved; the values of bow, warp, and total thickness variation (TTV) are all reduced after lapping. Under the same lapping conditions, the 6H-SiC has a smaller surface roughness than 4H-SiC, and for a specific crystalline form, the surface roughness of the C face is smaller than that of the Si face. The bow and warp of 4H-SiC are smaller, but the TTV is larger. The material removal rate is basically the same for 4H-SiC and 6H-SiC.

Microalgal lipids have drawn great attention as a promising sustainable resource for biodiesel or food supplement production. The development of high-performance strains of microalgae by metabolic engineering is invaluable for increasing the quantity or quality of desired lipids. The synthesis routes of lipids used as biodiesel in microalgae are based on fatty acid synthase (FAS) and triacylglycerols (TAG) biosynthesis pathway. Polyunsaturated fatty acids (PUFAs), including ω-6 and ω-3 fatty acids, are essential nutrients for humans. Notably, microalgae possess two distinct pathways for polyunsaturated fatty acids (PUFAs) biosynthesis, including the desaturase/elongase pathway and the polyketide synthase (PKS) pathway. Thus, it is necessary to identify which biosynthetic pathways are responsible for PUFA synthesis in particular microalgae species. In recent years, various key enzymes and functional domains involved in fatty acid and TAG biosynthesis pathway were identified and potentially regulated by genetic engineering approaches to elevate specific lipids content. In addition, other studies have reported the implementation of strategies to increase lipid accumulation based on increasing acetyl-CoA/NADPH supply, enhancing photosynthetic efficiency, or blocking competing pathways. Furthermore, other efforts have used transcription factor engineering to simultaneously regulate multiple genes related to lipid accumulation. This review summarizes recent research about a variety of microalgae lipid biosynthesis pathways, and discusses multiple gene manipulation strategies that have been employed for specific lipid overproduction in industrial microalgae.

We discovered a cooperative gold/silver catalysis mechanism in the oxidative cross-coupling reaction between 1,2,4,5-tetrafluorobenzene and N-TIPS-indole, using DFT calculations. A silver(I)-catalyzed CMD mechanism is responsible for the C-H activation of 1,2,4,5-tetrafluorobenzene, and C-H acidity determines the chemoselectivity. A gold(III)-catalyzed SE2Ar mechanism is responsible for the C3-H activation of N-TIPS-indole, and arene nucleophilicity determines the chemo- and regioselectivity. The orthogonal chemoselectivity control provides a mechanistic guide for dual C-H activation reactions.

Enzyme immobilization is widely applied in biocatalysis to improve stability and facilitate recovery and reuse of enzymes. However, high cost of supporting materials and laborious immobilization procedures has limited its industrial application and commercialization. In this study, we report a novel self-assembly immobilization system using bacteriophage T4 capsid as a nanocarrier. The system utilizes the binding sites of the small outer capsid protein, Soc, on the T4 capsid. Enzymes as Soc fusions constructed with regular molecular cloning technology expressed at the appropriate time during phage assembly and self-assembled onto the capsids. The proof of principle experiment was carried out by immobilizing β-galactosidase, and the system was successfully applied to the immobilization of an important glycomics enzyme, Peptide-N-Glycosidase F. Production of Peptide-N-Glycosidase F and simultaneous immobilization was finished within seven hours. Characterizations of the immobilized Peptide-N-Glycosidase F indicated high retention of activity and well reserved deglycosylation capacity. The immobilized Peptide-N-Glycosidase F was easily recycled by centrifugation and exhibited good stability that sustained five repeated uses. This novel system uses the self-amplified T4 capsid as the nanoparticle-type of supporting material, and operates with a self-assembly procedure, making it a simple and low-cost enzyme immobilization technology with promising application potentials.

Menaquinone-7 (MK-7) plays an important role in blood clotting, cardiovascular disease and anti-osteoporosis, and has been wildly used in the food additives and pharmaceutical industries. The aim of this study was to investigate the mechanism of menaquinone-7 biosynthesis in response to different oxygen supplies in Bacillus natto. The differences of fermentation performance, intracellular metabolites, oxidative stress reaction and enzyme activities of Bacillus natto R127 were analyzed under different KLa. Glycerol consumption rate and MK-7 yield at 24.76 min− 1 was 2.1 and 7.02 times of that at 18.23 min− 1. Oxidative stress analysis showed the cell generated more active oxygen and possessed higher antioxidant capacity at high oxygen supply condition. Meanwhile, high pyruvate kinase and high cytochrome c oxidase activities were also observed at 24.76 min− 1. Furthermore, comparative metabolomics analyses concluded series of biomarkers for high MK-7 biosynthesis and cell rapid growth. Besides, several metabolic responses including low glyceraldehyde-3-phosphate accumulation, low flux from pyruvate to lactic acid, high active TCA pathway, were also found to be associated with high MK-7 accumulation at high oxygen supply conditions. These findings provided the information for better understanding of oxygen effect on MK-7 biosynthesis and lay a foundation for further improvement of MK-7 production as well.

The aim of this work was to reduce the algae-residue emission and make use of cane molasses as fermentation materials for docosahexaenoic acid (DHA) fermentaion by Schizochytrium sp., which further could cut the cost of DHA production. Algae-residue and cane molasses were respectively used as nitrogen and carbon sources to replace yeast extract and glucose. A significant DHA yield of 18.58 g/L was obtained using algae-residue, while cane molasses could not be used well as sole carbon source due to the presence of undesirable substance. A two-stage culture strategy with glucose followed by pretreated cane molasses as carbon source was developed, resulting in a final DHA yield of 15.22 g/L. This study therefore offers an economical and green strategy for DHA production by Schizochytrium sp.

Ergothioneine is a sulfur-containing histidine derivative, that possessesexcellent antioxidant activity and has been used in the food and cosmetics industries. It plays a significant role in anti-aging and the prevention of various diseases. This review will briefly introduce the functions and applications of ergothioneine, elaborate the biosynthetic pathways of ergothioneine and describe several strategies to increase the production of ergothioneine. Then the efficient extraction and detection methods of ergothioneine will be presented. Finally, several proposals are put forward to increase the yield of ergothioneine, and the development prospects of ergothioneine will be discussed.

Background Cognitive decline occurs frequently in Parkinson’s disease (PD), which greatly decreases the quality of life of patients. However, the mechanisms remain to be investigated. Neuroinflammation mediated by overactivated microglia is a common pathological feature in multiple neurological disorders, including PD. This study is designed to explore the role of microglia in cognitive deficits by using a rotenone-induced mouse PD model. Methods To evaluate the role of microglia in rotenone-induced cognitive deficits, PLX3397, an inhibitor of colony-stimulating factor 1 receptor, and minocycline, a widely used antibiotic, were used to deplete or inactivate microglia, respectively. Cognitive performance of mice among groups was detected by Morris water maze, objective recognition, and passive avoidance tests. Neurodegeneration, synaptic loss, α-synuclein phosphorylation, glial activation, and apoptosis were determined by immunohistochemistry and Western blot or immunofluorescence staining. The gene expression of inflammatory factors and lipid peroxidation were further explored by using RT-PCR and ELISA kits, respectively. Results Rotenone dose-dependently induced cognitive deficits in mice by showing decreased performance of rotenone-treated mice in the novel objective recognition, passive avoidance, and Morris water maze compared with that of vehicle controls. Rotenone-induced cognitive decline was associated with neurodegeneration, synaptic loss, and Ser129-phosphorylation of α-synuclein and microglial activation in the hippocampal and cortical regions of mice. A time course experiment revealed that rotenone-induced microglial activation preceded neurodegeneration. Interestingly, microglial depletion by PLX3397 or inactivation by minocycline significantly reduced neuronal damage and α-synuclein pathology as well as improved cognitive performance in rotenone-injected mice. Mechanistically, PLX3397 and minocycline attenuated rotenone-induced astroglial activation and production of cytotoxic factors in mice. Reduced lipid peroxidation was also observed in mice treated with combined PLX3397 or minocycline and rotenonee compared with rotenone alone group. Finally, microglial depletion or inactivation was found to mitigate rotenone-induced neuronal apoptosis. Conclusions Taken together, our findings suggested that microglial activation contributes to cognitive impairments in a rotenone-induced mouse PD model via neuroinflammation, oxidative stress, and apoptosis, providing novel insight into the immunopathogensis of cognitive deficits in PD.

Sapphire substrates with different crystal orientations are widely used in optoelectronic applications. In this work, focused ion beam (FIB) milling of single-crystal sapphire with A-, C-, and M-orientations was performed. The material removal rate (MRR) and surface roughness (Sa) of sapphire with the three crystal orientations after FIB etching were derived. The experimental results show that: The MRR of A-plane sapphire is slightly higher than that of C-plane and M-plane sapphires, the Sa of A-plane sapphire after FIB treatment is the smallest among the three different crystal orientations. These results imply that A-plane sapphire allows easier material removal during FIB milling compared with C-plane and M-plane sapphires. Moreover, the surface quality of A-plane sapphire after FIB milling is better than that of C-plane and M-plane sapphires. The theoretical calculation results show that the removal energy of aluminum ions and oxygen ions per square nanometer on the outermost surface of A-plane sapphire is the smallest. This also implies that material is more easily removed from the surface of A-plane sapphire than the surface of C-plane and M-plane sapphires by FIB milling. In addition, it is also found that higher MRR leads to lower Sa and better surface quality of sapphire for FIB etching.

In this work, the reactive wetting and infiltration behaviors of a newly designed Sn-V binary alloy were comprehensively explored on porous graphite for the first time. It was discovered that 0.5 wt.% addition of V can obviously improve the wettability of liquid Sn on porous graphite and the nominal V contents in Sn-V binary alloys has minor effects on the apparent contact angles wetted at 950 &deg, C. Moreover, the V-containing Sn-V alloys were initiated to spread on porous graphite at ~650 &deg, C and reached a quasi-equilibrium state at ~900 &deg, C. Spreading kinetics of Sn-3V alloy on porous graphite well fitted in the classic product reaction controlled (PRC) model. However, our microstructural characterization demonstrated that, besides vanadium carbide formation, the adsorption of V element at the wetting three-phase contact line spontaneously contributed to the reactive spreading and infiltrating of Sn-V alloys on porous graphite. Meanwhile, the formation of continuous vanadium carbides could completely block the infiltration of Sn-V active solder alloy in porous graphite. Affected by the growth kinetics of vanadium carbides, the infiltration depth of Sn-V alloys in porous graphite decreased at increased isothermal wetting temperatures. This work is believed to provide implicative notions on the fabrication of graphite related materials and devices using novel V-containing bonding alloys.

A stable culture environment is the key for optimal growth and metabolic activity of microorganisms, especially in marine species, and intermittent feeding during DHA production using Schizochytrium sp. generates an unstable culture environment. To investigate the effect of unstable culture environment on the cells' physiological status and DHA synthesis, fermentations with different feeding strategies were performed on the lab scale. The intermittent feeding strategy caused fluctuations of substrate concentration and osmotic pressure, which had a negative effect on cell division and product synthesis. The physiological status and metabolic level of Schizochytrium sp. were relatively stable under a continuous feeding strategy with a relatively stable substrate concentration of 20-25 g/L, which was beneficial for the efficient transformation of substrate, leading to an improvement of DHA productivity. This strategy was further applied to pilot scale, whereby the DHA content, DHA productivity, convert ratio of glucose to lipid and DHA reached 55.02%, 320.17 mg/(L·h), 24.35%, and 13.40%, respectively. This study therefore provides an efficient strategy for ensuring a stable culture environment for the production of DHA and similar metabolites. Graphical Abstract.

Catechins are the major compounds in tea (Camellia sinenesis L.) and are responsible for its sensory qualities and health benefits. The study investigated the response of catechins biosynthesis to temperature changes in the controlled conditions and the possible mechanisms. The low-temperature treatment inhibited the growth of young shoots, suppressed the expression of catechins biosynthesis-related genes (except CsCHS3, CsDFR2, CsLAR2), and decreased the content of total esterified catechins but increased the content of total non-esterified catechins in tea plants. When the temperature increased from 15°C to 30°C, the young shoots grew faster, and the contents of total catechins, total esterified catechins and epigallocatechin gallate in tea plants increased by 87.7%, 92.5% and 53.6%, respectively. Meanwhile, the expression of growth-related genes was upregulated in the higher temperature treatment and was consistent with the response of catechins biosynthesis-related genes to temperature. The positive correlation and the cubic function (R2 > 90%) were noted between the growth of young shoots and catechins content. In brief, the response of catechins biosynthesis to temperature changes coordinately regulated by shoot growth and catechins genes expression of tea plants. Our findings provide the reference for improving tea quality by increasing its catechin contents.

Polymer-based dielectrics trigger great interests in advanced electric systems due to their high breakdown strength and power density. However, a major drawback is that excessive addition of high-er ceramic nanofillers may deteriorate their breakdown strength and further reduce energy density. Herein, a general strategy is provided to dramatically enhance the breakdown strength by introducing a small amount of core–shell structured Al2O3@BiFeO3 nanofibers into PVDF/PMMA polymer matrix. The thickness of BiFeO3 shell is regulated by controlling its molar concentration. A significantly enhanced breakdown strength (759 kV mm−1) and an ultrahigh energy density (22.7 J cm−3) with an energy efficiency of 72% are observed. The greatly improved breakdown strength is ascribed to the regulation of electron depletion layer. When the width of heterojunction region gradually approaches to the scale of electron depletion layer, more annihilation of electrons happens and thus contributes to the enhancement of the breakdown strength. The results suggest that our designed structure can help to address the issue of both enhancing the breakdown strength and energy density for diverse nanocomposites over a broad application.

Pneumocandin B0, the precursor of the antifungal drug caspofungin, is a secondary metabolite of the fungus Glarea lozoyensis. In this study, we investigated the effects of mannitol as the sole carbon source on pneumocandin B0 production by G. lozoyensis. The osmotic pressure is more important in enhancing pneumocandin B0 production than is the substrate concentration. Based on the kinetic analysis, an osmotic stress control fed-batch strategy was developed. This strategy led to a maximum pneumocandin B0 concentration of 2711 mg/L with a productivity of 9.05 mg/L/h, representing 34.67 and 6.47% improvements, respectively, over the best result achieved by the one-stage fermentation. Furthermore, G. lozoyensis accumulated glutamate and proline as compatible solutes to resist osmotic stress, and these amino acids also provided the precursors for the enhanced pneumocandin B0 production. Osmotic stress also activated ROS (reactive oxygen species)-dependent signal transduction by upregulating the levels of related genes and increasing intracellular ROS levels by 20%. We also provided a possible mechanism for pneumocandin B0 accumulation based on signal transduction. These findings will improve our understanding of the regulatory mechanisms of pneumocandin B0 biosynthesis and may be applied to improve secondary metabolite production.

Lipid accumulation of Schizochytrium sp. can be induced by stress condition, but this stress-induction usually reduce cell growth and cause oxidative damage, which can eventually lower the lipid yield. Here, adaptive laboratory evolution (ALE) combined high salinity was performed to enhance the antioxidant system and lipid accumulation. The final strain ALE150, which was obtained after 150 days, showed a maximal cell dry weight (CDW) of 134.5 g/L and lipid yield of 80.14 g/L, representing a 32.7 and 53.31% increase over the starting strain, respectively. Moreover, ALE150 exhibited an overall higher total antioxidant capacity (T-AOC) and lower reactive oxygen species (ROS) levels than the starting strain. Furthermore, the regulatory mechanisms responsible for the improved performance of ALE150 were analyzed by transcriptomic analysis. Genes related to the antioxidant enzymes and central carbon metabolism were up-regulation. Moreover, the metabolic fluxes towards the fatty acid synthase (FAS) and polyketide synthase (PKS) pathways were also changed.

The ω-3/long-chain polyunsaturated fatty acids (LC-PUFAs) play an important role in human health, but they cannot be synthesized in sufficient amounts by the human body. In a previous study, we obtained an engineered Schizochytrium sp. strain (HX-RS) by exchanging the acyltransferase (AT) gene, and it was able to co-produce docosahexaenoic acid and eicosapentaenoic acid. To investigate the mechanism underlying the increase of PUFA content in HX-RS, the discrepancies of fermentation performance, key enzyme activities and intracellular metabolites between HX-RS and its wild-type parent strain (WTS) were analyzed via fed-batch fermentation in 5-L bioreactors. The results showed that the cell dry weight (CDW) of HX-RS was higher than that of the WTS. Metabolomics combined with multivariate analysis showed that 4-aminobutyric acid, proline and glutamine are potential biomarkers associated with cell growth and lipid accumulation of HX-RS. Additionally, the shift of metabolic flux including a decrease of glyceraldehyde-3-phosphate content, high flux from pyruvate to acetyl-CoA, and a highly active glycolysis pathway were also found to be closely related to the high PUFA yield of the engineered strain. These findings provide new insights into the effects of exogenous AT gene expression on cell proliferation and fatty acid metabolism.

Background Schizochytrium sp. is a promising strain for the production of docosahexaenoic acid (DHA)-rich oil and biodiesel, and has been widely used in the food additive and bioenergy industries. Oxygen is a particularly important environmental factor for cell growth and DHA synthesis. In general, higher oxygen supply favors lipid accumulation, but could lead to a reduction of the DHA percentage in total fatty acids in Schizochytrium sp. To tackle this problem, it is essential to understand the mechanisms regulating the response of Schizochytrium sp. to oxygen. In this study, we aimed to explore the acclimatization of this DHA producer to different oxygen supply conditions by examining the transcriptome changes. Results Two different fermentation processes, namely normal oxygen supply condition (shift agitation speeds from 400 rpm to 300 rpm) and high oxygen supply condition (constant agitation speeds: 400 rpm), were designed to study how the fermentation characteristics of Schizochytrium sp. HX-308 were affected by different oxygen supply conditions. The results indicated that high oxygen supply condition resulted in 49% and 37.5% improvement in the maximum cell dry weight (CDW) and total lipid concentration, respectively. However, the DHA percentage in total fatty acids decreased to 35%, which was 31.4% lower than that produced by normal oxygen supply condition. Moreover, transcriptome analysis was performed to explore the effect of the oxygen supply condition on genetic expression and metabolism. The results showed that glycolysis and pentose phosphate pathway metabolism-associated genes (hexokinase, phosphofructokinase, fructose-bisphosphate aldolase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase) were substantially upregulated in response to high oxygen supply, resulting in more NADPH was available for Schizochytrium. Specially, high oxygen supply condition also led to genes (Δ6 desaturase, Δ12 desaturase, FAS, ORFA, ORFB, and ORFC) involved in fatty acid biosynthesis upregulation. In addition, a transcriptional upregulation of catalase (CAT) became apparent under high oxygen supply condition, while superoxide dismutase (SOD) and ascorbate peroxidase (APX) were found to be down-regulated. Conclusions This study is the first to investigate the differences of gene expression at different levels of oxygen availability in the DHA producer Schizochytrium. The results of transcriptome analyses indicated that high oxygen supply condition resulting in more NADPH and acetyl-CoA production for cell growth and lipid synthesis in Schizochytrium. Δ12 desaturase and ORFC showed higher expression levels at high oxygen supply condition, which might be the key regulators for enhancing fatty acid biosynthesis in the future. These results enrich the current knowledge regarding genetic expression and provide important information to enhance DHA production in Schizochytrium sp.

Metabolic profiling was used to discover mechanisms of increased pneumocandin B0 production in a high-yield strain by comparing it with its parent strain. Initially, 79 intracellular metabolites were identified, and the levels of 15 metabolites involved in six pathways were found to be directly correlated with pneumocandin B0 biosynthesis. Then by combining the analysis of key enzymes, acetyl-CoA and NADPH were identified as the main factors limiting pneumocandin B0 biosynthesis. Other metabolites, such as pyruvate, α-ketoglutaric acid, lactate, unsaturated fatty acids and previously unreported metabolite γ-aminobutyric acid were shown to play important roles in pneumocandin B0 biosynthesis and cell growth. Finally, the overall metabolic mechanism hypothesis was formulated and a rational feeding strategy was implemented that increased the pneumocandin B0 yield from 1821 to 2768 mg/L. These results provide practical and theoretical guidance for strain selection, medium optimization, and genetic engineering for pneumocandin B0 production.

The accumulation of reactive oxygen species (ROS) can induce oxidative damage which can be detrimental to microbial biomass and product yields. In this study, we used intermittent hypoxic stress (IHS) to eliminate the main source of ROS during the production of arachidonic acid (ARA)-rich lipids by Mortierella alpina. Biomass, lipid- and ARA concentration simultaneously reached their peak values, and the ARA yield increased by about 20% along with a lower level of ROS concentration. Under these conditions, more NADPH, substrate and energy may be available for lipid biosynthesis. The efficacy of this strategy was also confirmed in a bioreactor, with similar results. Interestingly, the total power required for stirring fell by about 4%, which may be of practical value for energy savings. This work offers new insights into the control of ROS generation in M. alpina and might be applicable to other microbial PUFAs producers.

Background Schizochytrium sp. is a marine microalga with great potential as a promising sustainable source of lipids rich in docosahexaenoic acid (DHA). This organism’s lipid accumulation machinery can be induced by various stress conditions, but this stress induction usually comes at the expense of lower biomass in industrial fermentations. Moreover, oxidative damage induced by various environmental stresses can result in the peroxidation of lipids, and especially polyunsaturated fatty acids, which causes unstable DHA production, but is often ignored in fermentation processes. Therefore, it is urgent to develop new production strains that not only have a high DHA production capacity, but also possess strong antioxidant defenses. Results Adaptive laboratory evolution (ALE) is an effective method for the development of beneficial phenotypes in industrial microorganisms. Here, a novel cooperative two-factor ALE strategy based on concomitant low temperature and high salinity was applied to improve the production capacity of Schizochytrium sp. Low-temperature conditions were used to improve the DHA content, and high salinity was applied to stimulate lipid accumulation and enhance the antioxidative defense systems of Schizochytrium sp. After 30 adaptation cycles, a maximal cell dry weight of 126.4 g/L and DHA yield of 38.12 g/L were obtained in the endpoint strain ALE-TF30, which was 27.42 and 57.52% higher than parental strain, respectively. Moreover, the fact that ALE-TF30 had the lowest concentrations of reactive oxygen species and malondialdehyde among all strains indicated that lipid peroxidation was greatly suppressed by the evolutionary process. Accordingly, the ALE-TF30 strain exhibited an overall increase of gene expression levels of antioxidant enzymes and polyketide synthases compared to the parental strain. Conclusion This study provides important clues on how to overcome the negative effects of lipid peroxidation on DHA production in Schizochytrium sp. Taken together, the cooperative two-factor ALE process can not only increase the accumulation of lipids rich in DHA, but also prevent the loss of produced lipid caused by lipid peroxidation. The strategy proposed here may provide a new and alternative direction for the industrial cultivation of oil-producing microalgae.

As one of the most important environmental factors, oxygen is particularly important for synthesis of n-3 polyunsaturated fatty acids (n-3 PUFA) in microalgae. In general, a higher oxygen supply is beneficial for cell growth but obstructs PUFA synthesis. The generation of reactive oxygen species (ROS) under aerobic conditions, which leads to the peroxidation of lipids and especially PUFA, is an inevitable aspect of life, but is often ignored in fermentation processes. Irritability, microalgal cells are able to activate a number of anti-oxidative defenses, and the lipid profile of many species is reported to be altered under oxidative stress. In this review, the effects of oxygen on the PUFA synthesis, sources of oxidative damage, and anti-oxidative defense systems of microalgae were summarized and discussed. Moreover, this review summarizes the published reports on microalgal biotechnology involving direct/indirect oxygen regulation and new bioreactor designs that enable the improved production of PUFA.

Process scale-up is a critical factor for realizing the industrial-scale production of docosahexaenoic acid (DHA). To improve the efficiency of scale-up, a strategy based on computational fluid dynamics analysis and investigation of microbial physiological properties was developed. We first investigated the physiological response of Schizochytrium sp. to different scale bioreactors, and the results indicated that a homogeneous culture environment was beneficial for cell growth and DHA biosynthesis. Fluid dynamics of different scale bioreactors were further investigated and impeller combinations were designed and optimized by computational methods to obtain a homogeneous culture environmental in a 7000 L bioreactor. The results showed that the optimal impeller combination could provide a more balanced culture environment, similar to lab-scale bioreactors. When the optimal strategy was used to scale-up the DHA fermentation, the biomass, DHA concentration, DHA percentage in biomass and DHA productivity reached 128.3 g/L, 39.2 g/L, 30.5%, 326.5 mg/(L h), respectively. This study thus introduces a highly efficient and economical scale-up strategy for DHA production using Schizochytrium sp.

In current study, a series of shikonin derivatives were synthesized and its anticancer activity was evaluated. As a result, PMMB232 showed the best antiproliferation activity with an IC50 value of 3.25±0.35μM. Further, treatment of HeLa cells with a variety of concentrations of target drug resulted in dose-dependent event marked by apoptosis. What's more, the mitochondrial potential (Δym) analysis was consistent with the apoptosis result. In addition, PARP was involved in the progress of apoptosis revealed by western blotting. To identify the detailed role and mechanism of PMMB232 in the progression of human cervical cancer, we detected the expression of HIF-1α and E-cadherin in HeLa cells. Results showed that expression of HIF-1α was downregulated, while E-cadherin protein was upregulated. Meanwhile, glycolysis related protein PDK1 was decreased in HeLa cells. Conversely, the expression of PDH-E1α was upregulated. Docking simulation results further indicate that PMMB232 could be well bound to HIF-1α. Taken together, our data indicate that compound PMMB232 could be developed as a potential anticancer agent.

Omega-3 fatty acids have received considerable attention due to their substantial health benefits. The aim of this study was to investigate the roles of acyltransferase (AT) domain and replace it for regulating fatty acid profile in Schizochytrium sp.. Herein, Schizochytrium sp. was engineered via gene deletion of AT and replacement of the native AT with its homologue, Shew-AT domain from Shewanella sp.. The docosahexaenoic acid (DHA) content in total fatty acids of the AT deficient strain observably decreased from 49.52% to 35.2% and the strain exhibited a low growth rate. Replacement with the Shew-AT gene recovered the cell growth and led to a high DHA content, with 3.7 times more eicosapentaenoic acid (EPA). This study will expand knowledge for synthesis of polyunsaturated fatty acid and facilitate the design of microbes with high yields of omega-3 fatty acids as a source of these valuable compounds for nutritional improvement.

Lutein is one of high-value added pigments from microalgae. Several energy-consuming methods for cell wall disruption have been developed due to the rigid cell wall of green algae. Ionic liquid - based approaches are considered as green technology for lutein extraction from microalgae. The structure and components of cell wall of microalgae are species specific so that it is necessary to select a suitable ionic liquid for lutein extraction. Two protocols using imidazolium-based ionic liquid from dried or fresh microalgae were evaluated for increasing the extraction efficiency of lutein from Chlorella sp. In the pretreatment process, [BMIM]Cl, [BMIM]Br, [EMIM]Cl and [EMIM]EtOSO3 were investigated. The concentration of these ionic liquids in aqueous solution, treatment temperature and time, and solid-liquid ratio (dried algae powder: ionic liquid aqueous solution) were also evaluated. The organic solvent and extraction times in lutein extraction process were also assessed. Compared with the protocol 1 (extraction from dried microalgae), extraction from fresh microalgae (protocol 2) had higher final lutein content and similar lutein extraction efficiency. Finally, the extraction efficiency was 97.73% when 10% [BMIM]Br was used to enhance cell disruption under 65 °C for 60 min for fresh microalgae. The solid-liquid ratio was 1:122. Diethyl ether was better than hexane, acetone and ethyl acetate as organic solvent. Seven times of extraction by organic solvent were enough and each time was 80 s. The current result is valuable for further development.

A sufficiently high oxygen supply is crucial for high-cell-density cultivation of aerobic microorganisms, including Schizochytrium sp. We, therefore, designed a novel bioreactor enabling high-level oxygen supply, and its relevant process parameters and fermentation-stage characteristics were investigated. The real-time changes of pH and nonoil biomass were monitored as proxies for the consumption of nitrogen and lipid accumulation status, which was first applied to divided fermentation process with three stages. The experimental results showed that the biomass in this porous-membrane-impeller bioreactor was higher than in conventional bioreactor, while docosahexaenoic acid (DHA) percentage in total lipids was lower than in conventional bioreactor. A multistage control strategy is subsequently implemented for the porous-membrane-impeller bioreactor, and the maximum biomass, DHA concentration, DHA percentage in biomass and DHA productivity reached 151.0 g/L, 44.3 g/L, 29.33%, 369.08 mg/(L·h), respectively. This study thus provides a highly efficient and economic bioreactor for the production of DHA by Schizochytrium sp. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4278–4286, 2017

Bacillus natto is commonly used in industrial production of menaquinone-7, an important vitamin which plays a crucial role for blood clotting and may contribute to prevention of cardiovascular disease and osteoporosis. This study determined the optimal combination of key nutrients and established an effective use of surfactant in a coupling medium to enhance the yield of extracellular MK-7. MK-7 yield of 31.18 mg/L was achieved under optimal conditions containing 53.6 g/L glycerol, 100 g/L soy peptone, and 10 g/L K2HPO4. A maximal yield of 40.96 mg/L MK-7 and a secretion ratio of 61.1% were obtained when 20 g/L soybean oil was supplemented at the logarithmic phase. The non-ionic surfactant span 20 was the second most promising surfactant in improving product yield, whereas addition of 2 g/L betaine exerted a minimal effect on secretion ratio of MK-7 at 19.1%. The results collectively showed that the supplementation of surfactants was an effective strategy to regulate cytomembrane permeability.

Yarrowia lipolytica, a non-conventional oleaginous yeast with special traits, has attracted increasing interest for producing value-added products. Generally, the DNA fragments of these heterologous metabolic pathways are constructed via the classic restriction digestion and ligation method. In contrast, the one-step in vivo pathway assembly method has been only rarely applied to Y. lipolytica. Here, with arachidonic acid biosynthesis as a case study, a one-step in vivo pathway assembly and integration method was used for engineering Y. lipolytica. Using rDNA as integrative locus, this study showed that there was a relation between the assembly efficiency and the length of overlapping region. Especially, with an overlap up to 1 kb, the method was able to rapidly assemble the arachidonic acid biosynthesis pathway (nearly 10 kb) into the chromosome with high efficiency (nearly 23%). Meanwhile, the pathway assembled in Y. lipolytica demonstrated long-term genetic stability and the engineered strain exhibited robust growth. Furthermore, this study demonstrated that the codon-optimized genes from Mortierella alpina can function efficiently in Y. lipolytica: a high level arachidonic acid production (0.4% of total fatty acids) was produced in the engineered strain. To our knowledge, this is the first time that this method is applied to Y. lipolytica for functional polyunsaturated fatty acids production. This method represents a powerful tool with potential for facilitating engineering applications in non-conventional yeasts.

TRANSPARENT TESTA1 (TT1) is a zinc finger protein that contains a WIP domain. It plays important roles in controlling differentiation and pigmentation of the seed coat endothelium, and can affect the expression of early biosynthetic genes and late biosynthetic genes of flavonoid biosynthesis in Arabidopsis thaliana. In Brassica napus (AACC, 2n=38), the functions of BnTT1 genes remain unknown and few studies have focused on their roles in fatty acid (FA) biosynthesis. In this study, BnTT1 family genes were silenced by RNA interference, which resulted in yellow rapeseed, abnormal testa development (a much thinner testa), decreased seed weight, and altered seed FA composition in B. napus. High-throughput sequencing of genes differentially expressed between developing transgenic B. napus and wild-type seeds revealed altered expression of numerous genes involved in flavonoid and FA biosynthesis. As a consequence of this altered expression, we detected a marked decrease of oleic acid (C18:1) and notable increases of linoleic acid (C18:2) and α-linolenic acid (C18:3) in mature transgenic B. napus seeds by gas chromatography and near-infrared reflectance spectroscopy. Meanwhile, liquid chromatography-mass spectrometry showed reduced accumulation of flavonoids in transgenic seeds. Therefore, we propose that BnTT1s are involved in the regulation of flavonoid biosynthesis, and may also play a role in FA biosynthesis in B. napus.

Oxygen-mediated cell damage is an important issue in aerobic fermentation. In order to counteract these problems, effect of ascorbic acid on cell growth and docosahexaenoic acid (DHA) production was investigated in Schizochytrium sp. Addition of 9g/L ascorbic acid resulted in 16.16% and 30.44% improvement in cell dry weight (CDW) and DHA yield, respectively. Moreover, the total antioxidant capacity (T-AOC) of cells decreased from 2.17 at 12h to 0 at 60h and did not recover, while ascorbic acid addition could extend the time of arrival zero with the reduced intracellular ROS. However, ROS levels still increased after 72h. Therefore, to further solve the problem of high ROS levels and low T-AOC of cells after 72h, a two-point addition strategy was proposed. With this strategy, DHA yield was further increased to 38.26g/L. This work innovatively investigated the feasibility of manipulating Schizochytrium sp. cultivation through ROS level and T-AOC.

Microalgae have attracted great attention as a promising sustainable resource for biofuel production. In studies aiming to improve lipid accumulation, many key enzymes involved in lipid biosynthesis were identified and confirmed, but genetic engineering remains a challenge in most species of microalgae. In an alternative approach, various chemical modulators can be used to directly regulate the lipid biosynthesis pathway, with similar effects to gene overexpression and interference approaches, including improving the precursor supply and blocking competing pathways. The produced lipid can be protected from being converted into other metabolites by the chemicals such as lipase inhibitors. In addition, a few chemicals were also demonstrated to greatly influence cell growth and lipid accumulation by indirect regulation of the lipid biosynthesis pathway, such as increasing cell permeability or regulating oxidative stress. Thus, adding chemical modulators can be a useful alternative strategy for improving lipid accumulation in large-scale cultivation of microalgae.

Tea powder, a biosorbent prepared from wasted oolong tea, was collected as a prospective adsorbent for the adsorption of methylene blue (MB) from aqueous solution. The effect of factors on adsorption efficiency, isotherms, kinetics, and potential mechanism was carried out. Adsorption capacity of MB onto wasted tea powder increased with the MB concentration and contact time, whereas the increase in pH value and ion strength appeared to have a negative effect for the adsorption process. The adsorption efficiency increased rapidly and reached a stable state within 120 min. The optimal tea powder loading weight is suggested to be at 0.1 to 0.2 g, and the highest efficiency of 94.8% is achieved at 333 K. There were no significant changes in adsorption efficiency when the effect of temperature is considered. The Langmuir isotherm model was found to be the best isotherm models to elucidate the adsorption mechanism in this study. The maximum adsorption capacities calculated at different temperatures by the Langmuir model ranging from 312.5 to 333.3 mg·g−1 were much close to the experimental results. From the kinetic analysis, the pseudo--second-order model was found to be the best model to describe the adsorption behavior. The calculated adsorption capacities at different initial MB concentrations by the pseudo-second-order model ranging from 92.34 to 400 mg·g−1 were well close to the experimental data. The fitting results obtained from the intraparticle diffusion model suggested that the intraparticle diffusion was not the only rate-controlling step and some other mechanisms along with the intraparticle diffusion were probably involved. The intraparticle diffusion of MB molecules into pore structures of wasted tea powder is the rate-limiting step for the adsorption process in this study. The repetitive cycle experiments indicated that the wasted oolong tea powder was efficiently regenerated using NaOH and thus be used for many times.

Temperature is an important factor that not only affects cell growth, but also changes fatty acid composition in oleaginous microorganisms. Here, adaptive laboratory evolution (ALE) was performed in Schizochytrium sp. to enhance strain thermotolerance in docosahexaeonic acid (DHA) production. The adaptive strain showed higher growth rate and lower temperature sensitivity. Cell growth rate of the adaptive strain after 70 cycles at high temperature stimulation (ALE70) at 28 °C and 34 °C were 46.93% and 60.55% higher than that of original strain. Meanwhile, the reduction ratio of DHA yield from 28 °C to 34 °C of ALE70 decreased by 61.71%. Finally, lipid and DHA concentration at 34 °C reached 4.31 and 4.33 times of the starting strain. Further physiological analysis showed ALE70 generated less ROS, synthesized less HSP proteins, and produced more pigments, which might be related to the improved performance. This work increased the fermentation temperature by 5 degrees without affecting DHA production, which significantly reduced the energy consumption cost of the industrialization.

In recent years, mobile consumer electronics and electric vehicles have been developing rapidly, and they have been hunting for lithium batteries with high energy density, high safety and stability, to alleviate the range anxiety and improve their stability over long term operations. These make all-solid-state lithium batteries very attractive and they have been under intense investigations. However, the development of high-performance all-solid-state lithium batteries requires an in-depth understanding of their charge and discharge mechanism, their degradation process, along with the evolution of the microstructures, phase compositions, chemical states and their distributions, etc., inside the battery and at the interface. This paper summarizes the basic principles, functions, and the representative advances in investigation of the dynamics and failure mechanism of electrode materials and interfaces in solid-state lithium batteries under working conditions, with typical in-situ characterization techniques, including in-situ microscopy (in-situ scanning electron microscopy (SEM), in-situ transmission electron microscopy (TEM)), in-situ X-ray techniques (in-situ X-ray diffraction (XRD)), in-situ X-ray photoelectron spectroscopy (XPS), in-situ near-edge structure X-ray absorption spectroscopy (XANES), in-situ X-ray tomography), in-situ neutron techniques (in-situ neutron diffraction (ND), in-situ neutron depth profiling (NDP)) and in-situ spectroscopies (in-situ Raman spectroscopy, in-situ nuclear magnetic resonance (NMR) and in-situ nuclear magnetic resonance imaging (MRI)), etc. We also discussed the application of future advanced in-situ characterization techniques in the investigation of all-solid-state lithium batteries.

Feed efficiency (FE) is essential for pig production. In this study, 300 significantly differentially expressed (DE) transcripts, including 232 annotated genes, 28 cis-natural antisense transcripts (cis-NATs), and 40 long noncoding RNAs (lncRNAs), were identified between the liver of Yorkshire pigs with extremely high and low FE. Among these transcripts, 25 DE lncRNAs were significantly correlated with 125 DE annotated genes at a transcriptional level. These DE genes were enriched primarily in vitamin A (VA), fatty acid, and steroid hormone metabolism. VA metabolism is regulated by energy status, and active derivatives of VA metabolism can regulate fatty acid and steroid hormones metabolism. The key genes of VA metabolism (CYP1A1, ALDH1A2, and RDH16), fatty acid biosynthesis (FASN, SCD, CYP2J2, and ANKRD23), and steroid hormone metabolism (CYP1A1, HSD17B2, and UGT2B4) were significantly upregulated in the liver of high-FE pigs. Previous study with the same samples indicated that the mitochondrial function and energy expenditure were reduced in the muscle tissue of high-FE pigs. In conclusion, VA metabolism in liver tissues plays important roles in the regulation of FE in pigs by affecting energy metabolism, which may mediate fatty acid biosynthesis and steroid hormone metabolism. Furthermore, our results identified novel transcripts, such as cis-NATs and lncRNAs, which are also involved in the regulation of FE in pigs.

Vitamin K2 (menaquinone or MK) plays an important role in blood clotting, cardiovascular disease, and anti-osteoporosis. A novel bacterial strain was isolated and identified as Bacillus natto based on 16SrDNA sequencing and LC-MS analysis. The objective of this study was to improve the extraction efficiency and productivity of MK-7 from B. natto. Acid-heating method efficiently disrupted B. natto cells for MK-7 extraction. Bacillus natto had a wide range of pH (5.0 ~ 9.0) for optimal growth. Its MK-7 yield was increased when rotation speed was increased to 200 rpm. The highest MK-7 yield was obtained when glycerol and soy peptone were used in the growth media. Batch fermentation was subsequently tested in 5 L bioreactor, which gave a high productivity of MK-7 (at 0.60 mg/L/h). A positive correlation between MK-7 yield and sporulation ratio was also found. This study provides valuable information on the extraction and production of menaquinone-7 from B. natto under submerged fermentation condition.

A combination of microbial strain improvement and statistical optimization is investigated to maximize pneumocandin B0 production from Glarea lozoyensis ATCC 74030. Atmospheric and room temperature plasma (ARTP) was used to enhance G. lozoyensis ATCC 74030 in pneumocandin B0 yield. Mutant strain G. lozoyensis Q1 exhibited 1.39-fold increase in pneumocandin B0 production to 1134 mg/L when compared with the parent strain (810 mg/L). Further, the optimized medium provided another 1.65-fold in final pneumocandin B0 concentration to 1873 mg/L compared to the original medium. The results of this study indicated the combined application of a classical mutation and medium optimization can improve effectively pneumocandin B0 production from G. lozoyensis and could be a tool to improve other secondary metabolites production by fungal strains.

Intrinsic microcrystalline silicon thin film were prepared by VHF-PECVD, the activation energy of thin film were measured by activation energy testing equipment. The activation energy of samples with different crystalline volume fraction and prepared at different power and different pressure were studied. The results showed that: the activation energy of samples deposited at amorphous/microcrystalline transition zone decrease as crystalline volume fraction increasing. With increasing of depositing power and pressure, the depositing rate were increased, the activation energy were also increased, the oxygen contaminate could be suppressed by increasing depositing rate by increasing depositing power and pressure.

A ZrB 2 –SiO 2 coating was prepared on the SiC coated carbon/carbon composites by infiltrating silica sol into a porous ZrB 2 layer. The ZrB 2 –SiO 2 coating protected the composites from oxidation for 330 h at 1500 °C with a weight loss of 158 g/m 2 . The formation of ZrO 2 and ZrSiO 4 from ZrB 2 expanded the volume of solid phase, generating compressive stress in the coating at high-temperature oxidations. The phase transformation of ZrO 2 provided the compressive stress in the coating during cooling. These compressive stresses restrained the formation of cracks and improved the oxidation protection of the coating.