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Highlights • BIT could seriously inhibit microalgal growth by damaging the photosynthetic system. • Microalgae could recover from the inhibition if BIT concentration was not high. • BIT consumption was the primary reason for algal growth recovery. • Microalgae were still alive even if their growth was completely inhibited. • SOD, CAT and GSH played a key role in algal detoxification against BIT poisoning. Abstract Isothiazolinones, such as 1,2-benzisothiazol-3(2H)-one (BIT), are widely used as biocides for bacterial growth control in many domestic and industrial processes. Despite their advantages as biocides, they are highly toxic and pose a potential risk to the environment. This study investigated the inhibition process and detoxification mechanism involved in microalgal survival and growth recovery after BIT poisoning. BIT could seriously inhibit the growth of Scenedesmus sp. LX1, Chlorella sp. HQ, and Chlamydomonas reinhardtii with half maximal effective concentrations at 72 h (72h-EC 50) of 1.70, 0.41, and 1.16 mg/L, respectively. The primary inhibition mechanism was the BIT-induced damage to microalgal photosynthetic systems. However, the inhibited strains could recover when their growth was not completely inhibited. The influence of this inhibiting effect on subsequent algal regrowth was negligible or weak. BIT consumption was the primary reason for their recovery. Notably, algae did not die even if their growth was completely inhibited. If the BIT concentration did not exceed a certain high level, then the inhibited algae could recover their growth relatively well. Microalgal generation of reduced glutathione (GSH) and the oxygen radical scavenging enzymes, superoxide dismutase (SOD) and catalase (CAT), played a key role in detoxification against BIT poisoning. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Rare ginsenosides were successfully bio-transformed by Aspergillus tubingensis. • Rh4 aglycone increased over 100 folds than that in the original TSSLG. • MCL-1 was explored as anticancer target of Rh4 and its aglycone. Abstract Rare ginsenoside Rh 4 and its aglycone are present in low levels in Panax ginseng. This study focused on achieving ginsenoside Rh 4 and its aglycone by microbial transformation of the total saponins of stems and leaves of P. ginseng (TSSLG). A total of 78 fungal strains isolated from the rhizosphere soil of P. ginseng , and one of them, Aspergillus tubingensis , was found to be capable of biotransformation of TSSLG to ginsenoside Rh4 and its aglycone with high efficiency, especially the content of ginsenoside Rh4 aglycone was enhanced 100 folds over than that in the original TSSLG. Compared with ginsenoside Rg3 (named ShenYi capsule as antitumor drug in China), ginsenoside Rh4 aglycone exhibited stronger antitumor activity against human cancer cell lines SGC-7901, KB-A-1 and HT-1080. The possible biotransformation pathways of ginsenoside Rh4 and its aglycone were speculated according to the chemical structures. The anticancer binding-target, myeloid cell leukemia 1 protein (MCL-1), was explored using molecular docking analysis and the possible combination mechanism was discussed. [ABSTRACT FROM AUTHOR]

Methylisothiazolinone (MIT) has been widely used to control bacterial growth in reverse osmosis (RO) systems. However, MIT's toxicity on microalgae should be determined because residual MIT is concentrated into RO concentrate (ROC) and might have a severe impact on microalgae-based ROC treatment. This study investigated the tolerance of Scenedesmus sp. LX1 to MIT and revealed the mechanism of algal growth inhibition and toxicity resistance. Scenedesmus sp. LX1 was inhibited by MIT with a half-maximal effective concentration at 72 h (72 h-EC 50 ) of 1.00 mg/L, but the strain recovered from the inhibition when its growth was not completely inhibited. It was observed that this inhibition's effect on subsequent growth was weak, and the removal of MIT was the primary reason for the recovery. Properly increasing the initial algal density significantly shortened the adaptation time for accelerated recovery in a MIT-containing culture. Photosynthesis damage by MIT was one of the primary reasons for growth inhibition, but microalgal cell respiration and adenosine triphosphate (ATP) synthesis were not completely inhibited, and the algae were still alive even when growth was completely inhibited, which was notably different from observations made with bacteria and fungi. The algae synthesized more chlorophyll, antioxidant enzymes of superoxide dismutase (SOD) and catalase (CAT), and small molecules, such as reduced glutathione (GSH), to resist MIT poisoning. The microalgae-based process could treat the MIT-containing ROC, since MIT was added for only several hours a week in municipal wastewater reclamation RO processes, and the MIT average concentration was considerably lower than the maximum concentration that algae could tolerate. [ABSTRACT FROM AUTHOR]

A total of 58 fungal isolates, belonging to 24 genera, were obtained from the leaves, stems and roots of Ginkgo biloba L.. Among them, one endophytic fungal strain, Penicillium cataractum SYPF 7131, displayed the strongest antibacterial activity. Four new compounds ( 1 – 4) were isolated from the strain fermentation broth together with four known compounds ( 5 – 8) . These structures were determined on the basis of 1D and 2D NMR and [Rh 2 (OCOCF 3 ) 4 ]-induced electronic circular dichroism (ECD) spectroscopic analyses. All the isolated compounds were screened for their in vitro antimicrobial activities. Compound 3 and 4 showed moderate inhibitory activity against Staphylococcus aureus . Compound 7 exhibited significant inhibitory activity against S. aureus with MIC value of 10 μg/mL. Further, the in silico molecular docking studies of the active compounds was used to explore the binding interactions with the active site of filamentous temperature-sensitive protein Z (FtsZ) from Staphylococcus aureus . The docking results revealed that compounds 3 , 4 and 7 showed high binding energies, strong H-bond interactions and hydrophobic interactions with FtsZ from S. aureus validating the observed antimicrobial activity. Based on antimicrobial activities and docking studies, compounds 3 , 4 and 7 were identified as promising antimicrobial lead molecules. [ABSTRACT FROM AUTHOR]

In many microalgal cultivation systems, microalgae co-exist with bacteria, while little is known about the characteristics of their symbiotic relationships. In this study, twenty-six microalgae growth-promoting bacteria were isolated from a culture system of Scenedesmus sp. LX1 cultivated in the secondary effluent from domestic wastewater by using the high-throughput multiple well plate screening method. Ten strains were found to produce and secrete indole acetic acid (IAA), promoting the growth of microalgae. Meanwhile, the microalgae might have secreted signal substances to induce IAA production in bacteria, which was amplified in the tryptophan abundant environment. This indicates that bacteria may mainly promote the growth of the co-existing microalgae through secreting IAA, and microalgae would selectively enhance IAA secretion in turn. Microalgae cultured with microalgal growth-promoting bacteria would be a new potential strategy for improving large-scale microalgal cultivation in an economic and environmentally-friendly way. [ABSTRACT FROM AUTHOR]

Heterotrophic cultivation of Chlorella pyrenoidosa based on straw substrate was proposed as a promising approach in this research. The straw pre-treated by ammonium sulfite method was enzymatically hydrolyzed for medium preparation. The highest intrinsic growth rate of C. pyrenoidosa reached to 0.097 h −1 in hydrolysate medium, which was quicker than that in glucose medium. Rising nitrogen concentration could significantly increase protein content and decrease lipid content in biomass, meanwhile fatty acids composition kept stable. The highest protein and lipid content in microalgal biomass reached to 62% and 32% under nitrogen excessive and deficient conditions, respectively. Over 40% of amino acids and fatty acids in biomass belonged to essential amino acids (EAA) and essential fatty acids (EFA), which were qualified for high-value uses. This research revealed the rapid biomass accumulation property of C. pyrenoidosa in straw hydrolysate medium and the effectiveness of nitrogen regulation to biomass composition at heterotrophic condition. [ABSTRACT FROM AUTHOR]

Microalgae cultivation is a promising candidate for autotrophic sequestrating CO 2 transformation into renewable bio-products. However, potential of microalgae has not been fully explored due to the bottlenecks of biomass harvesting during large-scale microalgae cultivation. A novel capillary-driven photobioreactor (CPBR) is proposed in this study for attached microalgae cultivation obtaining high biomass productivity and overcoming the biomass harvesting limitation in traditional suspended cultures. Performances on microalgal growth, cellular composition, nutrients uptake from water, and corresponding light utilization efficiencies were investigated and emphasized. During 12 days of system operation, attached microalgal biomass on the carriers were in the range of 83.6 g/m 2 -footprint area of 121.5 g/m 2 -footprint area, corresponding to light utilization efficiency of 3.3% to 4.8%. With proper carriers packing density of 16% to 32%, obtained biomass productivities of CPBR were approximately 10 g/m 2 /d (footprint area). Biomass composition analysis revealed that lipid and carbohydrates contents in attached microalgal biomass were higher than in suspended microalgal biomass with same cultivating conditions, proving the potential of microalgae cultivated in CPBR as feedstock of biofuels. [ABSTRACT FROM AUTHOR]

Gene engineered mesenchymal stem cells (MSCs) have been proposed as promising tools for their various applications in biomedicine. Nevertheless, the lack of an effective and safe way to genetically modify these stem cells is still a major obstacle in the current studies. Herein, we designed novel magnetic complexes by assembling cationized pullulan derivatives with magnetic iron oxide nanoparticles for delivering target genes to MSCs. Results showed that this complexes achieved effective gene expression with the assistance of external magnetic field, and resisted the adverse effect induced by serum proteins on the gene delivery. Moreover, neither significant cytotoxicity nor the interference on the osteogenic differentiation to MSCs were observed after magnetofection. Further studies revealed that this effective and serum resistant gene transfection was partly due to the accelerated and enhanced intracellular uptake process driven by external magnetic field. To conclude, the current study presented a novel option for genetic modification of MSCs in an effective, relatively safe and serum compatible way. [ABSTRACT FROM AUTHOR]

Carbon trading is an important market instrument and policy tool to promote China's practice of low-carbon energy conservation and strive to achieve carbon peaking by 2030 and carbon neutrality by 2060. To improve market flow and respond to the national strategy to support the development of carbon trading in China, a smart carbon trading process optimization framework based on blockchain technology is developed in this article. First, the paper analyzes the current state of carbon trading in China's power sector and identifies the future development trend and barriers to carbon trading in China. Second, a framework for a smart carbon trading system based on the structure and traits of blockchain technology is created to optimize the carbon trading process. Third, the smart contract for the smart carbon trading system is built (including execution logic, transaction matching, contract fulfillment, and other elements). This mechanism measures the reputation of trading users. Finally, policy suggestions are provided to solve the current issues and challenges. According to the research conducted for this paper on "blockchain + carbon trading in China," carbon trading supported by blockchain technology can guarantee transaction security and efficiency, accurately preserve transaction records, and offer a high level of automated settlement. [ABSTRACT FROM AUTHOR]

Microalgae-based bioenergy has been long considered as a promising substitute to replace the fossil fuels at large-scale. After the decades of research, several bottlenecks remain to be overcome to make the large-scale production of microalgal bioenergy commercially viable. In this review, the bottlenecks that restrict the commercial production of microalgal bioenergy are summarized as “high cost” and “low efficiency” and then identified in detailed categories. Several solutions which aim to solve the bottlenecks are presented and discussed correspondingly. The solutions presented in this review including cultivating in wastewater, recycling water and nutrients, utilizing the whole biomass, selecting indigenous strains, cultivating mixed-species, supplementing low-cost organic substrates, mixing vertically in reactor, optimizing metabolic pathway and attaching the cells on suspended-solids. Furthermore, a novel system integrated with the solutions, which is combined with the wastewater treatment system and characterized as the mixed-species cultivation of wild-selected mixotrophic microalgal strains in suspended-solid phase bioreactor based on low-cost substrate, is proposed to promote the scale-up of the microalgal cultivation for bioenergy production. [ABSTRACT FROM AUTHOR]

Objective Chlamydia psittaci is an avian respiratory pathogen and zoonotic agent. The wide prevalence of C. psittaci poses a threat to the poultry industry and its employees. However, few commercial kits are available for detecting avian antibodies excluding the in-house ELISA kit. In this study, we developed a novel ELISA kit for detecting antibodies against C. psittaci based on the N-terminal fragment of polymorphic outer membrane protein D (PmpD-N) as the coating antigen. Methods The antigen concentrations, primary antibody, and cut-off value were determined and optimized. The ELISA, designated PmpD-N ELISA, was assessed for sensitivity, specificity, and concordance using sera samples from 48 experimentally infected and 168 uninfected SPF chickens. Results The sensitivity and specificity of PmpD-N ELISA were 97.9%, 100%, respectively, while the concordance was 98.1% as compared to that of MOMP-ELISA. No cross-reaction with positive sera for other avian pathogens was found. Using PmpD-N ELISA, 799/836 clinical samples were positive, including 93.0% and 98.1% positivity in layers and broilers, respectively. Conclusion These data indicate that indirect ELISA with PmpD-N as the antigen candidate is a promising approach for the surveillance of C. psittaci infection. [ABSTRACT FROM AUTHOR]

Abstract: One of the main limitations of anti-tumor gene therapy is the lack of an effective way to deliver therapeutic genes to tumor sites. Bone marrow mesenchymal stem cells (BMSCs) have been proposed as cellular delivery vehicles to tumor sites in tumor-targeted cancer gene therapy. Here, we investigated the therapeutic effects of cytomegalovirus-thymidine kinase expressing BMSCs (TK-BMSCs) on pulmonary melanoma metastasis combined with prodrug ganciclovir. BMSCs were successfully engineered through a non-viral gene vector. The gene recombinant BMSCs migrated to the pulmonary area and were found to have the tendency to target tumor nodules after systemic delivery. In vitro results demonstrate that the engineered BMSCs have significant suicide effects in the presence of ganciclovir in a dose-dependent manner and can exert a sufficient bystander effect on B16F10 tumor cells in co-culture experiments. In vivo studies confirmed the therapeutic effects of TK-BMSCs/ganciclovir on the metastasis tumor model. From the Clinical Editor: This study investigates the possibility of gene transfer via bone marrow mesenchymal stem cells in anti-cancer gene therapy using a metastatic melanoma model and cytomegalovirus-thymidine kinase expressing stem cells, demonstrating clear therapeutic effects. [Copyright &y& Elsevier]

Abstract: This study aims to investigate the efficacy of chitosan nanoparticles (CS-NPs) as a vehicle for transcutaneous antigen delivery in anti-tumor therapy. Ovalbumin (OVA) or gp100 (melanocyte-associated antigen gp100 protein)-loaded CS-sodium tripolyphosphate (TPP)-grafted NPs were prepared by crosslinking low-molecular-weight CS with TPP. Compared with the FITC-OVA solution, the encapsulated fluorescein isothiocyanate (FITC)-OVA-loaded NPs expressed much stronger cellular uptake ability in vitro and higher ability to migrate to lymph nodes in vivo. After transcutaneous administration, OVA-loaded NPs, with imiquimod as an adjuvant, increased the anti-OVA immunoglobulin G titer to levels similar to those induced by the OVA solution. The gp100-loaded NPs promoted the survival of tumor-bearing mice. These results provided evidence of CS-NPs as promising carriers for transcutaneous vaccine delivery, partly contributing to the increased uptake of NPs by skin antigen-presenting cells as well as their enhanced migration to the surrounding lymph nodes. From the Clinical Editor: In this study the efficacy of chitosan nanoparticle based vehicles for transcutaneous antigen delivery is investigated in anti-tumor therapy. Authors demonstrate that such nanoparticles may be efficient carriers partly due to their increased uptake by antigen-presenting cells in the skin and their enhanced migration to surrounding lymph nodes. [Copyright &y& Elsevier]

Highlights: [•] Three mixotrophic microalgae strains were isolated from wastewater treatment plant. [•] Heterotrophically cultivate the strains in domestic wastewater under dark condition. [•] The strains obtained high-lipid contents during the heterotrophic cultivation. [•] Over half of DOC in wastewater was removed by the microalgae strains. [•] Assimilation efficiency of DOC in domestic wastewater for the strains was acquired. [ABSTRACT FROM AUTHOR]

Highlights: [•] Soluble algae products could significantly inhibit the growth of Scenedesmus sp. LX1. [•] All of the fractions of SAP could inhibit the growth of Scenedesmus sp. LX1. [•] Organic bases and HIA expressed the strongest inhibition on growth. [•] HIA could significantly inhibit the lipid accumulation of Scenedesmus sp. LX1. [•] Molecular weight and fluorescence spectroscopy of HIA were investigated. [Copyright &y& Elsevier]

• Phosphonates showed weak effects on algal growth at the initial cultivation stage. • 10 d-EC 50 of HEDP and DTPMP on S. LX1 were 57.6 and 35.7 mg/L, respectively. • Phosphonates blocked algal assimilation of iron ions by complexation. • Iron deficiency hindered photosynthesis, leading to complete growth inhibition. • Intrinsic toxicity of the phosphonates toward algal cells was negligible. The effects of phosphonates, the heavily-used antiscalants in reverse osmosis systems, on microalgae are controversial, although they are harmless to most aquatic organisms. Herein, we assessed the inhibitory effects of etidronic acid (HEDP) and diethylenetriamine penta(methylene phosphonic acid) (DTPMP) on algal growth and revealed the mechanisms involved in both intrinsic toxicity and complexation. The phosphonates showed weak influences on Scenedesmus sp. LX1 in the first 4 d of cultivation. In contrast, a significant growth inhibition was observed subsequently with half maximal effective concentrations of 57.6 and 35.7 mg/L for HEDP and DTPMP, respectively, at 10 d. The phosphonates had little effect on cellular energy transfer and oxidative stress, quantified by adenosine triphosphate level and superoxide dismutase activity, respectively, demonstrating weak intrinsic toxicities to algal cells. Phosphonates blocked the algal assimilation of iron ions through complexation. Severe iron deficiency limited photosynthetic activity and caused chlorophyll decline, resulting in a functional loss of the photosystem followed by complete algal growth inhibition at the late cultivation stage. Our findings point to a potential ecological impact wherein harmful algal blooms are induced by the natural degradation of phosphonates due to the release of both iron and phosphate ions that stimulate algal regrowth after disinhibition. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• 6-benzylaminopurine affects algae in a dose-dependent manner. • Low dosage of 6-benzylaminopurine increased microalgal biomass accumulation. • Low dosage of 6-benzylaminopurine increased the yield of fatty acid methyl esters. • 6-benzylaminopurine enhanced microalgal photosynthetic activity. • Microalgal metabolic activity was enhanced by lower dosage 6-benzylaminopurine. Microalgae have great potential for use in the production of valuable products. However, the low productivity of microalgal cultures is a bottleneck that restricts their large-scale application. In this study, the effects of an artificial, synthetic plant growth-promoting substance, 6-benzylaminopurine (6-BA), on the growth characteristics and physiology of Scenedesmus sp. LX1 was investigated. The results showed that 6-BA affected microalgae growth and physiology in a dose-dependent manner; low doses promoted growth while high doses inhibited growth. At the optimum dose (0.1 mg L−1), the maximum algal density and the maximum population growth rate were increased by 20% and 52%, respectively, compared with the control. Meanwhile, the yield of fatty acid methyl esters (FAME) also increased, and their compositions were changed, which resulted in an increase in monounsaturated fatty acid content at lower doses. The rates of nitrogen and phosphorus uptake were also enhanced at low doses. The measurement of photosynthetic activity in the microalgae indicated that lower doses of 6-BA enhanced activity by increasing the amounts of chlorophyll, which promoted the growth of microalgae. Metabolic activity analysis showed that lower doses of 6-BA enhanced dehydrogenase activity and ATP accumulation in microalgal cells. Overall, this study shows that 6-BA has a high potential for use in the development efficient microalgal culture systems. [ABSTRACT FROM AUTHOR]

Abstract A total of 180 fungal isolates, belonging to 20 genera and 47 species, were obtained from the roots, stems and leaves of Panax notoginseng. One isolate, the endophytic fungus Penicillium janthinellum SYPF 7899, displayed the strongest antibacterial activity and was studied for its production of secondary metabolites. In total, three new compounds, including rotational isomers 1a, 1b and 2 were isolated from the solid cultures of P. janthinellum , as well as eight known compounds (3 − 10). These structures were determined on the basis of 1D, 2D NMR and electronic circular dichroism (ECD) spectroscopic analyses as well as theoretical calculations. Compound 1 exhibited significant inhibitory activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 15 and 18 μg/ml, respectively. The other compounds showed moderate or weak activities. In addition, morphological observation showed the rod-shaped cells of B. subtilis growing into long filaments, which reached 1.5- to 2-fold of the length of the original cells after treatment with compound 1. The coccoid cells of S. aureus exhibited a similar response and swelled to a 2-fold volume after treatment with compound 1. In silico molecular docking was explored to study the binding interactions between the compounds and the active sites of filamentous temperature-sensitive protein Z (FtsZ) from B. subtilis and S. aureus. Compound 1a, 1b and 2 showed high binding energies, strong H-bond interactions and hydrophobic interactions with FtsZ. Based on the antimicrobial activities, cellular phenotype observation and docking studies, compound 1 is considered to be a promising antimicrobial inhibitor of FtsZ. Graphical Abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) have been regarded as potential targeting vehicles and demonstrated to exert therapeutic benefits for brain diseases. Direct homing to diseased tissue is crucial for stem cell-based therapy. In this study, a peptide-based targeting approach was established to enhance cell homing to cerebral ischemic lesion. Palmitic acid–peptide painted onto the cell membrane was able to direct MSCs to ischemic tissues without any observed cell cytotoxicity and influence on differentiation, thus reducing accumulation of cells in peripheral organs and increasing engraftment of cells in the targeted tissues. With enhanced cell homing, MSCs were used to deliver miR-133b to increase the expression level of miR-133b in an ischemic lesion and further improve therapeutic effects. This study is the first to develop MSCs co-modified with targeting peptide and microRNAs as potential targeting therapeutic agents. This targeting delivery system is expected to be applicable to other cell types and other diseases aside from stroke. [ABSTRACT FROM AUTHOR]

While reverse osmosis (RO) is a promising technology for wastewater reclamation, RO concentrate (ROC) treatment and disposal are important issues to consider. Conventional chemical and physical treatment methods for ROC present certain limitations, such as relatively low nitrogen and phosphorus removal efficiencies as well as the requirement of an extra process for hardness removal. This study proposes a novel biological approach for simultaneous removal of nitrogen, phosphorus, and calcium (Ca 2+ ) and magnesium (Mg 2+ ) ions from the ROC of municipal wastewater treatment plants by microalgal cultivation and algal biomass production. Two microalgae strains, Chlorella sp. ZTY4 and Scenedesmus sp. LX1, were used for batch cultivation of 14–16 days. Both strains grew well in ROC with average biomass production of 318.7 mg/L and lipid contents up to 30.6%, and nitrogen and phosphorus could be effectively removed with efficiencies of up to 89.8% and 92.7%, respectively. Approximately 55.9%–83.7% Ca 2+ could be removed from the system using the cultured strains. Mg 2+ removal began when Ca 2+ precipitation ceased, and the removal efficiency of the ion could reach up to 56.0%. The most decisive factor influencing Ca 2+ and Mg 2+ removal was chemical precipitation with increases in pH caused by algal growth. The results of this study provide a new biological approach for removing nitrogen, phosphorous, and hardness from ROC. The results suggest that microalgal cultivation presents new opportunities for applying an algal process to ROC treatment. The proposed approach serves dual purposes of nutrient and hardness reduction and production of lipid rich micro-algal biomass. [ABSTRACT FROM AUTHOR]

As 1,2-benzisothiazol-3(2H)-one (BIT) has been widely used in high concentrations for microbial growth control in many domestic and industrial processes, its potential eco-risk should be assessed. This study investigated the interaction between BIT and microalgae in aquatic environment as the mechanism of BIT lethal effect on microalgae was unclear and whether microalgae could efficiently remove BIT was unknown. It was found that Chlorella vulgaris could be killed by high concentrations of BIT, and this lethal effect was strongly enhanced when exposed to light. Inhibition of photosystem II electron transport followed by a decrease in cellular chlorophyll led to serious damage to algal photosynthesis. The excess accumulation of reactive oxygen species caused by the photosynthetic damage under light further increased the oxidative damage and promoted cell death. Under dark condition, however, the algae could tolerate higher BIT concentrations. BIT could be efficiently removed when the growth of Scenedesmus sp. LX1 was not completely inhibited. With an initial concentration of 4.5 mg/L, over 99% of BIT was removed during 168 hour cultivation. Microalgal biodegradation was the primary reason for this removal, and the contributions of BIT hydrolytic/photolytic degradation, microalgal growth, photosynthesis and sorption were negligibly small. These results pointed to the potential application of microalgae for efficient BIT removal from wastewater. Unlabelled Image • BIT lethal effect was strongly enhanced when microalgae was exposed to light. • Electron transport inhibition and chlorophyll decrease led to photosynthetic damage. • Excess ROS accumulation increased photo-oxidative damage and promoted cell death. • BIT could be completely removed with high efficiency by microalgal cultivation. • Microalgal biodegradation was the primary reason for BIT removal. [ABSTRACT FROM AUTHOR]

Attached microalgae cultivation could simplify the microalgae harvest process and reduce its associated cost, which has attracted much attention recently. In this paper, the reactor patterns, advantages, microalgae biomass productivity, influencing factors and the microalgae physicochemical properties in the attached microalgae cultivation was summarized to show the sketch of this novel microalgae cultivation. It was concluded that the attached microalgae cultivation is advantageous in achieving less water and space consumption, higher water treatment potential and higher biomass productivity compared with the traditional suspended microalgae cultivation. The accumulation of the attached microalgae biomass showed a linear increase with culture time with the largest productivity up to 20.7 g m −2 d −1 . Chlorella and Scenedesmus were the top two species that have been studied in attached culture system. Cellulose acetate/nitrate membrane, polycarbonate membrane and cotton were the most popular materials used owing to their high hydrophilicity and wide availability. Flow rate, nutrients, light, CO 2 and other factors could affect the attached microalgae productivity and the physicochemical property in a way different from the suspended microalgae, which were described in detail in this review. At last, some technical bottlenecks and the corresponding solvents in the attached microalgae were suggested. [ABSTRACT FROM AUTHOR]

Microalgae are potential candidates for the production of valuable products, such as renewable biodiesel, health products and pigments. However, low biomass productivity has restricted their large-scale applications. In this study, the effects of two auxins (one natural type of indole-3-acetic acid (IAA) and the other synthetic type of 2,4-dichlorophenoxyacetic acid (2,4-D)) on the growth and fatty acid methyl esters (FAMEs) production of a freshwater microalgae Scenedesmus sp. LX1 were investigated. Both auxins showed a “low dosage-promotion and high dosage-inhibition” effect on the growth and FAMEs accumulation. The optimum dosage of IAA and 2,4-D were 1 mg L −1 and 0.1 mg L −1 , respectively. Moreover, the IAA could increase the monounsaturated fatty acid content. The auxins may promote the growth by enhancing the photosynthetic activity through increasing chlorophyll contents. Therefore, auxin significantly enhanced microalgal growth and FAMEs accumulation, and has a potential for application in developing efficient microalgal cultivation. [ABSTRACT FROM AUTHOR]

Nowadays, microalgae-based bioenergy has been commonly considered as a potential substitute of the non-renewable traditional energy resources with increasing attention. Nevertheless, microalgal cells will secrete/release some Soluble Algal Products (SAPs) into the culture medium during microalgal biomass cultivation. Studies on the influences, especially the negative ones, of SAPs in large-scale cultivation of microalgae for biomass/bioenergy production remain limited. The negative effects, properties, production and treatments of SAPs were therefore investigated and summarized in this paper. It was found that SAPs may inhibit microalgal growth, raise the cost of microalgal recovery and lower the performance of the downstream discharged water treatment process after microalgal cultivation, among others. The production of SAPs could be as high as 70 mg/L in terms of dissolved organic carbon (DOC), causing substantial environmental issues. The chemical properties of SAPs significantly varied among different microalgal species, growth phases and nutrient concentrations. The distribution of molecular weight of SAPs varied from less than 1 kDa to more than 100 kDa, meanwhile the hydrophilic/hydrophobic property of SAPs showed a consistency. All studies showed that more than 60% of SAPs are hydrophilic. After comparing three different SAPs treatment methods, it was concluded that biodegradation could be a feasible and economical process to remove SAPs based on the properties of SAPs. The mechanisms of SAPs formation and the mitigation of their undesirable effects are still not clear. Therefore, a systematic and deep study on those topics is urgently needed. [ABSTRACT FROM AUTHOR]

Abstract: Using wastewater as resource for microalgal cultivation was seriously considered as a promising approach for sustainable biomass and lipid production. The proper selection of microalgal species is the foundation and key point to achieve this objective. This paper reviewed the recent status of microalgal cultivation in wastewater, including the characteristics of microalgal species used in recent studies, the performance of different microalgal species in different types of wastewater, the commonly-used isolation methods of microalgal species adaptable to the growth in wastewater, and the evaluation criteria of microalgal species. It was found that microalgal biomass and lipid production in wastewater were comparable to those in artificial culture medium, although most of the data was obtained in sterilized wastewater. Among all microalgal species involved in this review, Botryococcus braunii, Chlorella pyrenoidosa and Chlamydomonas reinhardtii showed superior performance in certain studies. However, no microalgal species has been demonstrated to meet all the requirements for large-scale biomass production in wastewater. Thus, the efforts on microalgal species isolation and characterization should still be promoted. On the basis of all the information, this review explored the limitations of recent studies and future research needs on this topic. [Copyright &y& Elsevier]

Highlights: [•] Solid carriers were added and kept suspended by aeration in this ssPBR. [•] Microalgae could attach and grow on the carriers. [•] By catching carriers, microalgae could easily be separated from liquid phase. [•] Biomass production in ssPBR was increased by adding solid carriers. [Copyright &y& Elsevier]

Microalgal growth is the key to the coupled system of wastewater treatment and microalgal biomass production. In this study, Monod model, Droop model and Steele model were incorporated to obtain an integrated growth model describing the combined effects of nitrogen, phosphorus and light intensity on the growth rate of Scenedesmus sp. LX1. The model parameters were obtained via fitting experimental data to these classical models. Furthermore, the biomass production of Scenedesmus sp. LX1 in open pond under nutrient level of secondary effluent was analyzed based on the integrated model, predicting a maximal microalgal biomass production rate about 20 g m −2 d −1 . In order to optimize the biomass production of open pond the microalgal biomass concentration, light intensity on the surface of open pond, total depth of culture medium and hydraulic retention time should be 500 g m −3 , 16,000 lx, 0.2 m and 5.2 d in the conditions of this study, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Novel NO absorbent–releaser is discovered by utilizing the as-synthesized mesoporous silica MCM-41 or MCM-48, not only saving the energy and time for removal of template, but also establishing the way to utilize the micelles for new applications of health care. The micelles of cetyltrimethylammonium bromide (CTAB) in the as-synthesized MCM-48 or MCM-41 have a configuration of spoke-like in the wheel or net-like inside the channel, intercepting and capturing the NO in gas flow with an unwonted high absorption capacity. Once NO is absorbed on these composites, it forms surface nitrous species and nitrates that are stable in atmosphere, achieving the storage of NO in ambient environment. Finally, the NO can be acid-triggered released in the solution with the pH value same as that of the gastric juice, providing a new low-cost candidate for delivering exogenous NO. Various factors, including surfactant types, framework structures, and absorption temperatures, are investigated to expatiate this new controllable absorption–release process, exploiting further the utilization of micelles and affording a new application of as-synthesized mesoporous material in the drug delivery system. [Copyright &y& Elsevier]

Abstract: The present study reports the cloning and sequencing of lac2 from Bacillus subtilis. The gene is composed of 1542bp and encodes a 514-amino acid protein. The gene has 86% homology with a published laccase with GeneID 936023. The lac2 gene was deposited in GenBank as a new nucleotide sequence. This new sequence was cloned into the multiple cloning site of pPIC9K to generate pPIC9K-lac2, which was then transformed into Pichia pastoris GS115 via electroporation. The recombinant GS115 (pPIC9K-lac2) was grown initially in BMGY medium and transferred to BMMY to induce gene expression for 48h. The recombinant Lac2 protein shows laccase activity with α-naphthol and guaiacol as substrates. The optimal pH is between 3.2 and 4.7, and the optimal temperature is 25°C for enzyme reaction. [Copyright &y& Elsevier]

• Suspended-solid phase cultivation with repeated carrier addition enhanced growth. • Maximum algal growth rate (212.2 mg/(L∙d)) increased by 41% • An optimal carrier addition model for algal growth enhancement was developed. • Over 91% of nitrogen and phosphorus were removed from ROC with high efficiency. • Hardness precursors and extremely high concentrations of MIT were well removed. The disposal of reverse osmosis (RO) concentrate (ROC) is a critical challenge impeding the application of RO-based wastewater reclamation. Herein, we proposed an enhanced biotreatment approach for the simultaneous removal of nitrogen, phosphorous, hardness, and methylisothiazolinone (MIT) from ROC by suspended-solid phase cultivation of Scenedesmus sp. LX1. Repeated carrier addition, guided by the developed optimal carrier addition model, efficiently enhanced algal growth and contaminant removal through dynamically controlling the suspended algal density by cell attachment. The maximum algal growth rate (212.2 mg/(L∙d)) increased by 41% compared with the control, and the time needed for reaching the maximum algal biomass (906.7 mg/L) was shortened by 1 d, attributing to the mitigation of density restriction. 91.8% of nitrogen (30.2 mg/L) was removed with 5.5 mg/(L∙d) accelerating removal rate, and phosphate (3.7 mg/L) was completely removed within 1 d. Hardness precursors calcium and inorganic carbon were also removed in large amounts, 268.4 and 128.2 mg/L, respectively. Moreover, suspended-solid phase cultivation significantly mitigated the growth inhibition caused by MIT toxicity, enabled the algae to completely biodegrade MIT of extremely high concentrations (4.7 mg/L and 11.4 mg/L) in a short time. Our results demonstrate the feasibility of suspended-solid phase algal cultivation for simultaneously and effectively removing multiple main contaminants from ROC. [ABSTRACT FROM AUTHOR]