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Android is the most widely used mobile operating system (OS). A large number of third-party Android application (app) markets have emerged. The absence of third-party market regulation has prompted research institutions to propose different malware detection techniques. However, due to improvements of malware itself and Android system, it is difficult to design a detection method that can efficiently and effectively detect malicious apps for a long time. Meanwhile, adopting more features will increase the complexity of the model and the computational cost of the system. Permissions play a vital role in the security of the Android apps. Term Frequency—Inverse Document Frequency (TF-IDF) is used to assess the importance of a word for a file set in a corpus. The static analysis method does not need to run the app. It can efficiently and accurately extract the permissions from an app. Based on this cognition and perspective, in this paper, a new static detection method based on TF-IDF and Machine Learning is proposed. The system permissions are extracted in Android application package's (Apk's) manifest file. TF-IDF algorithm is used to calculate the permission value (PV) of each permission and the sensitivity value of apk (SVOA) of each app. The SVOA and the number of the used permissions are learned and tested by machine learning. 6070 benign apps and 9419 malware are used to evaluate the proposed approach. The experiment results show that only use dangerous permissions or the number of used permissions can't accurately distinguish whether an app is malicious or benign. For malware detection, the proposed approach achieve up to 99.5% accuracy and the learning and training time only needs 0.05s. For malware families detection, the accuracy is 99.6%. The results indicate that the method for unknown/new sample's detection accuracy is 92.71%. Compared against other state-of-the-art approaches, the proposed approach is more effective by detecting malware and malware families. [ABSTRACT FROM AUTHOR]

Airborne bacteria were measured when a dust storm passed Beijing in spring 2012 with a focus on cell concentration, viability and TSA- and R2A-cultured strain composition. The concentration varied at an order of 10 7 cells/m 3 with dust loading (demonstrated with PM 10 ) and they had a very close correlation ( R T 2 = 0.91, p < 0.01). At the time of highest PM 10 of 652 μg/m 3 , the bacterial concentration reached 1.4 × 10 8 cells/m 3 , which was larger than that before and after the dust event by one order. Bacterial viability, the ratio of number concentration of viable cells to total cells, was 32%–64% and smaller in the dust plume than that before the dust arrival. Bacterial strains from the culture ranged between 2.5 × 10 4 and 4.6 × 10 5 CFU/m 3 and no correlation with PM 10 was determined. Their composition was different before and after the dust arrival according to 16S rRNA gene sequences and strains belong to Actinomycetes and Firmicutes were the majority in the dust samples. [ABSTRACT FROM AUTHOR]

Mechanoresponsive luminescence (MRL) have great potential applications in the fields of sensing, displaying, optical information storage and damage detection because of their light emission or color changing response under mechanical stimulation. In this work, 1,1,2,2-tetrakis (4-nitrophenyl) ethane (TPE-4N) has been synthesized as a MRL with aggregation induced emission (AIE) properties. Taking advantage of the high contrast of mechanically sensitive fluorescence of TPE-4N under mechanical stimulation, it has been coated on the various laminated fiber reinforced composites (FRCs) to successfully realize the on-site visualization of stress distribution of composites. V-shear experiments were carried out on three types of laminated FRCs coated with TPE-4N coatings. The experimental results show that TPE-4N can transform the invisible stress distribution information into visible fluorescence information. Moreover, the matrix cracking, fibre fracture and delamination of the composites can be qualitatively analyzed by using the fluorescence visualization images. By considering the repairability of FRC, early warning values were introduced by calculating the fluorescence areas. The fluorescence visualization method proposed in this work demonstrates the great potential in on-site monitoring the structural health condition of engineering composite structures. [Display omitted] • The on-site visualization of stress distribution of CFRCs with different structures has been achieved with TPE-4N coatings. • Different damage types of the CFRCs can be qualitatively analyzed by the fluorescence visualization. • Early warning values of CFRCs are proposed based on the fluorescence visualization by considering the repairability of CFRCs. [ABSTRACT FROM AUTHOR]

Highlights: [•] Environmental factors were proved to be helpful to lipid accumulation. [•] NaCl, Fe3+ and nitrogen starvation together made lipid content increase to 2.5 times. [•] Both high and low temperature could promote lipid accumulation. [•] UTEX 2341 was proved to be a potential species for high-quality biodiesel production. [ABSTRACT FROM AUTHOR]

Abstract: High production cost is a major obstacle to the extensive use of microalgae biodiesel. To cut the cost and achieve higher biomass productivity, Chlorella minutissima UTEX2341 was cultured under photoheterotrophic conditions. With the carbon, nitrogen and phosphorus concentration of 26.37, 2.61 and 0.03gL−1 d−1 respectively, a maximum biomass productivity of 1.78gL−1 d−1 was obtained, which was 59 times more than that cultured under autotrophic condition. The lipid productivity reached 0.29gL−1 d−1, which was 11.9 times higher than the highest value reported by . The conversion rate of microalgae lipids to FAME was found to be elevated from 45.65% to 62.97% and the FAME productivity increased from 1.16 to 180.68mgL−1 d−1 after the optimization. 94% of the fatty acid of C. minutissima UTEX2341 was found to be composed of palmitic, oleic, linoleic and γ linoleic and the unsaturated fatty acids were the main parts (79.42%). [Copyright &y& Elsevier]

Previous study showed that nitrogen content in lignite humic acids (HA) increased significantly during lignite biodegradation. In this paper we evaluated the factors responsible for the increased level of N in HA and the formation of new nitrogen compound following microbial degradation. When the ammonium sulfate concentration in lignite medium was < 0.5%, the N-content in HA was higher than that in the crude lignite humic acid (cHA); when the ammonium sulfate concentration was ≥ 0.5%, both the biodegraded humic acid (bHA) N-content and the content of bHA in lignite increased significantly, but at 2.0% no increase was observed. This indicated that HA incorporated N existing in the lignite medium, and more HA can incorporate more N with the increase of bHA amount in lignite during microbial degradation. CP/MAS 15N NMR analysis showed that the N incorporated into HA during biotransformation was in the form of free or ionized NH2-groups in amino acids and sugars, as well as NH4+. We propose nitrogen can be incorporated into HA biotically and abiotically. The high N content bHA has a potential application in agriculture since N is essential for plant growth. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the feasibility of bioflocculant extraction from backwashing sludge to reduce its production costs was investigated. Results showed that ultrasound and base treatment could significantly enhance bioflocculant extraction efficiency, however, flocculating activity was affected. It was observed that bioflocculants extracted from sludge of pH 11.0 had no flocculating activity. In contrast, bioflocculants extracted from sludge of pH 5.0, named as M-1, had good flocculating activity. To further study the flocculating activity of M-1, factors such as bioflocculant dosage, temperature and pH of the reaction solution were tested. The optimal conditions were 6.0mg/l bioflocculant dosage and pH 5.0, at a temperature of 10°C. Under these conditions, the flocculating rate of kaolin clay was 92.67%. The effectiveness of such bioflocculants in the decolorization of synthetically dyed wastewater was then examined. In flocculating methylene blue and fast blue in aqueous solutions, decolorization efficiency levels were 82.9% and 77.8%, respectively. [Copyright &y& Elsevier]

[Display omitted] • The conjugate electrospinning facilitates the scalable manufacture of fiber. • Best fluorescent performance is achieved with optimal spinning parameters. • The fluorescence intensity of fiber is proportional to the spinning rate. • The fiber reserves 90% fluorescence intensity after stretching and bending. • The light-emitting fabrics are proved effective as smart textiles. Flexible, lightweight and practical luminous fibers have aroused great interest in the field of smart textiles. In this study, we report flexible aggregation induced emission luminogen (AIEgen) fibers which can be produced in a continuous and large-scale way. Fluorescent nanofibers prepared by conjugate electrospinning are wrapped on the surface of flexible core fiber to form a skin-core AIEgen fiber. The electrospinning parameters including spinning concentration, traction rate, spinning rate and tetraphenylethylene (TPE) concentration were designed and optimized via the non-interactive orthogonal experimental design. The optimized flexible AIEgen fiber retains the excellent mechanical properties of core fiber and is equipped with the fluorescence properties of the wrapped fluorescent nanofibers. In addition, the fabricated AIEgen fibers can still exhibit good fluorescence characteristic after being stretched, bent, washed and rubbed, displaying excellent durability. Different from reported luminescent fibers which required an external power supply or complicated preparation process, the flexible AIEgen fibers fabricated in this study can be prepared continuously in a large-scale way and exhibits effectiveness in clothing display, anti-counterfeiting, information transmission and hazardous gas detection, which shows great application potential for wearable smart textiles. [ABSTRACT FROM AUTHOR]

Abstract: The uptake of cadmium and responses to this metal were studied in growing Rhodotorula sp. Y11. In presence of cadmium, Y11 showed a similar lag phase with decreased μ max in comparison to the control cultures in the absence of cadmium. Different changes in contents of cell elemental composition (carotenoids, total protein, total soluble sugar, and phosphate content) were observed under cadmium pressure. Growing Rhodotorula sp. Y11 took up cadmium in a biphasic mode, involving an initial energy-independent biosorption to the cell surface, followed by a slower energy-dependent intracellular accumulation. In the presence of metabolic inhibitors, intracellular cadmium uptake of growing Y11 was significantly influenced. [Copyright &y& Elsevier]

Abstract: The process involved in lignite degradation/solubilization by Penicillium decumbens P6 was studied. P6 secreted some unknown alkaline substance and increased the pH of the medium as it grew. Meanwhile, it excreted some surfactants that might be involved in lignite degradation. The most important aspect in this study was that P6 could excrete some extracellular enzymes that might participate in the lignite degradation. With the induction of lignite, the activities of peroxidases and esterases, two classes of enzymes capable of attacking lignite, were increased in the cell-free filtrate of the culture. [Copyright &y& Elsevier]

Millions of Android applications (apps) are widely used today. Meanwhile, the number of malicious apps has increased exponentially. Currently, there are many security detection technologies for Android apps, such as static detection and dynamic detection. However, the uncertainty of the features in detection is not considered sufficiently in these technologies. Permissions play an important role in the security detection of Android apps. In this paper, a malicious application detection model based on features uncertainty (MADFU) is proposed. MADFU uses logistic regression function to describe the input (permissions) and output (labels) relationship. Moreover, it uses the Markov chain Monte Carlo (MCMC) algorithm to solve features' uncertainty. After experimenting with 2037 samples, for malware detection, MADFU achieves an accuracy of up to 95.5%, and the false positive rate (FPR) is 1.2%. MADFU's Android app detection accuracy is higher than the accuracy of directly using 24 dangerous permission. The results also indicate that the method for an unknown/new sample's detection accuracy is 92.7%. Compared to other state-of-the-art approaches, the proposed method is more effective and efficient, by detecting malware. [ABSTRACT FROM AUTHOR]

Microbial communities that inhabit the host's intestine influence many aspects of the host's health and bear the adaptive potential to alterations in harsh environments and diets. The Qinghai‐Tibet Plateau represents one of the harshest environments in the world. Preliminary progress has been made in identifying the communities of gut microbes in Indigenous Tibetans and non‐human animals. However, due to the complexity of microbial communities, the effects of gut microbes on the host's health and high‐plateau adaptation remain unexplained. Herein, we review the latest progress in identifying factors affecting the gut microbiota of native Tibetans and non‐human animals and highlight the complex interactions between the gut microbiota, health and highland adaptation, which provides a basis for exploring the correlations between the gut microbiota and clinical indexes in native highland residents and travellers, as well as developing microbiota‐based strategies to mitigate health risks for tourists and treatments for mountain sickness during high‐altitude travel in the future. [ABSTRACT FROM AUTHOR]

Symbiotic nitrogen fixation (SNF) is a crucial process for nitrogen geochemical cycling and plant‐microbe interactions. Water‐soluble humic acid (WSHM), an active component of soil humus, has been shown to promote SNF in the legume‐rhizobial symbiosis, but its molecular mechanism remains largely unknown. To reveal the SNF‐promoting mechanism, we conducted transcriptomic analysis on soybean treated with WSHM. Our findings revealed that up‐ and downregulated differentially expressed genes (DEGs) were mainly involved in plant cell‐wall/membrane formation and plant defence/immunity in the early stage, while the late stage was marked by the flavonoid synthesis and ethylene biosynthetic process. Further study on representative DEGs showed that WSHM could inhibit GmBAK1d‐mediated immunity and BR signalling, thereby promoting rhizobial colonisation, infection, and nodulation, while not favoring pathogenic bacteria colonisation on the host plant. Additionally, we also found that the ethylene pathway is necessary for promoting the soybean nodulation by WSHM. This study not only provides a significant advance in our understanding of the molecular mechanism of WSHM in promoting SNF, but also provides evidence of the beneficial interactions among the biostimulator, host plant, and soil microbes, which have not been previously reported. Summary Statement: Water‐soluble humic acid promoted soybean‐rhizobia symbiosis and nodulation by inhibiting host immunity and ethylene pathway, without sacrificing defence to the pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Background: As part of the plant microbiome, endophytic bacteria play an essential role in plant growth and resistance to stress. Water-soluble humic materials (WSHM) is widely used in sustainable agriculture as a natural and non-polluting plant growth regulator to promote the growth of plants and beneficial bacteria. However, the mechanisms of WSHM to promote plant growth and the evidence for commensal endophytic bacteria interaction with their host remain largely unknown. Here, 16S rRNA gene sequencing, transcriptomic analysis, and culture-based methods were used to reveal the underlying mechanisms. Results: WSHM reduced the alpha diversity of soybean endophytic bacteria, but increased the bacterial interactions and further selectively enriched the potentially beneficial bacteria. Meanwhile, WSHM regulated the expression of various genes related to the MAPK signaling pathway, plant-pathogen interaction, hormone signal transduction, and synthetic pathways in soybean root. Omics integration analysis showed that Sphingobium was the genus closest to the significantly changed genes in WSHM treatment. The inoculation of endophytic Sphingobium sp. TBBS4 isolated from soybean significantly improved soybean nodulation and growth by increasing della gene expression and reducing ethylene release. Conclusion: All the results revealed that WSHM promotes soybean nodulation and growth by selectively regulating soybean gene expression and regulating the endophytic bacterial community, Sphingobium was the key bacterium involved in plant-microbe interaction. These findings refined our understanding of the mechanism of WSHM promoting soybean nodulation and growth and provided novel evidence for plant-endophyte interaction. [ABSTRACT FROM AUTHOR]

Andrimid is a potent antibiotic that inhibits acetyl-CoA carboxylase. However, its low biological yield and complex chemical synthesis have hindered its large-scale application. In this study, we found that the LysR-type transcriptional activator AdmX controls andrimid yield by adjusting its expression level in the andrimid-producing bacterium Erwinia persicina strain BST187. Our results showed that gradually increasing of admX transcriptional levels significantly improved andrimid yield, while the yield declined when admX was overexpressed excessively. To further estimate the effect of AdmX on andrimid promotion, we fitted and developed a model which was y = −0.5576x2 + 61.945x + 800.63 (R2 = 0.9591), where x represents the admX transcriptional level and y represents andrimid yield. Andrimid yield of admX overexpression strain BST187ΔadmX/pET28a-Pgap-1::admX was greatly improved by 260%, which was reported for the first time that andrimid yield could be promoted by genetic engineering. Thus, this study provides important insights that the biosynthesis of andrimid would be improved by bioengineering and sheds lights on the potential application of andrimid in both biomedicine and bioagricultural manipulation with its large-scale production in the future. Key points: • Andrimid production can be greatly promoted by genetic engineering on non-model chassis. • The relationship between AdmX abundance and andrimid yield in Erwinia persicina strain BST187 might be parabolic. • Erwinia persicina BST187 combined with chassis modification enable the promising applications in andrimid industrialization. [ABSTRACT FROM AUTHOR]

Xylanolytic enzymes, with both endo‐xylanase and arabinoxylan arabinofuranohydrolase (AXH) activities, are attractive for the economically feasible conversion of recalcitrant arabinoxylan. However, their characterization and utilization of these enzymes in biotechnological applications have been limited. Here, we characterize a novel bifunctional enzyme, rAbf43A, cloned from a bacterial consortium that exhibits AXH and endo‐xylanase activities. Hydrolytic pattern analyses revealed that the AXH activity belongs to AXHd3 because it attacked only the C(O)‐3‐linked arabinofuranosyl residues of double‐substituted xylopyranosyl units of arabinoxylan and arabinoxylan‐derived oligosaccharides, which are usually resistant to hydrolysis. The enzyme rAbf43A also liberated a series of xylo‐oligosaccharides (XOSs) from beechwood xylan, xylohexaose and xylopentaose, indicating that rAbf43A exhibited endo‐xylanase activity. Homology modelling based on AlphaFold2 and site‐directed mutagenesis identified three non‐catalytic residues (H161, A270 and L505) located in the substrate‐binding pocket essential for its dual‐functionality, while the mutation of A117 located in the −1 subsite to the proline residue only affected its endo‐xylanase activity. Additionally, rAbf43A showed significant synergistic action with the bifunctional xylanase/feruloyl esterase rXyn10A/Fae1A from the same bacterial consortium on insoluble wheat arabinoxylan and de‐starched wheat bran degradation. When rXyn10A/Fae1A was added to the rAbf43A pre‐hydrolyzed reactions, the amount of released reducing sugars, xylose and ferulic acid increased by 9.43% and 25.16%, 189.37% and 93.54%, 31.39% and 32.30%, respectively, in comparison with the sum of hydrolysis products released by each enzyme alone. The unique characteristics of rAbf43A position it as a promising candidate not only for designing high‐performance enzyme cocktails but also for investigating the structure–function relationship of GH43 multifunctional enzymes. [ABSTRACT FROM AUTHOR]

Background: After centuries of heavy reliance on fossil fuel energy, the world suffers from an energy crisis and global warming, calling for carbon emission reduction and a transition to clean energy. Microalgae have attracted much attention as a potential feedstock for biofuel production due to their high triacylglycerol content and CO2 sequestration ability. Many diacylglycerol acyltransferases (DGAT) species have been characterized, which catalyze the final committed step in triacylglycerol biosynthesis. However, the detailed structure–function features of DGATs and the role of the interactions among DGAT proteins in lipid metabolism remained largely unknown. Results: In this study, the three characterized DGATs of Auxenochlorella protothecoides 2341 showed distinct structural and functional conservation. Functional complementation analyses showed that ApDGAT1 had higher activity than ApDGAT2b in yeast and model microalgae, and ApDGAT2a had no activity in yeast. The N-terminus was not essential to the catalysis function of ApDGAT1 but was crucial to ApDGAT2b as its enzyme activity was sensitive to any N-terminus modifications. Similarly, when acyl-CoA binding proteins (ACBPs) were fused to the N-terminus of ApDGAT1 and ApDGAT2b, zero and significant activity changes were observed, respectively. Interestingly, the ApACBP3 + ApDGAT1 variant contributed to higher oil accumulation than the original DGAT1, and ApACBP1 + ApDGAT1 fusion boosted oleic acid content in yeast. Overexpression of the three DGATs and the variation of ApACBP3 + ApDGAT1 increased the content of C18:1 of Chlamydomonas reinhardtii CC-5235. Significantly, ApDGAT1 interacted with itself, ApDGAT2b, and ApACBP1, which indicated that these three lipid metabolic proteins might have been a part of a dynamic protein interactome that facilitated the enrichment of oleic acid. Conclusions: This study provided new insights into the functional and structural characteristics of DGATs and elucidated the importance of these physical interactions in potential lipid channeling. [ABSTRACT FROM AUTHOR]

The economical production of 5‐aminolevulinic acid (ALA) has recently received increasing attention for its extensive use in agriculture. In this study, a strain of Bacillus cereus PT1 could initially produce ALA at a titre of 251.72 mg/L by using a hydrolysate mixture of low‐cost cassava residue and fish waste. The integration of endogenous hemA encoding glutamyl‐tRNA reductase led to a 39.30% increase in ALA production. Moreover, improving cell permeability by deletion of the LytR‐CpsA‐Psr (LCP) family gene tagU led to a further increase of 59.73% in ALA production. Finally, the engineered strain B. cereus PT1‐hemA‐ΔtagU produced 2.62 g/L of ALA from the previously mentioned hydrolysate mixture in a 7‐L bioreactor. In a pot experiment, foliar spray of the ALA produced by B. cereus PT1‐hemA‐ΔtagU from the hydrolysates increased salt tolerance of cucumber by improving chlorophyll content and catalase activity, while decreasing malondialdehyde content. Overall, this study demonstrated an economic way to produce ALA using a microbial platform and evidenced the potential of ALA in agricultural application. [ABSTRACT FROM AUTHOR]

Temperature is a crucial factor affecting microalgae CO 2 capture and utilization. However, an in-depth understanding of how microalgae respond to temperature stress is still unclear. In particular, the regulation mechanism under opposite temperature (heat and cold) stress had not yet been reported. In this study, the physicochemical properties and transcription level of related genes of microalgae Auxenochlorella protothecoides UTEX 2341 under heat and cold stress were investigated. Heat stress (Hs) caused a drastic increase of reactive oxygen species (ROS) in UTEX 2341. As key elements responded to Hs, superoxide dismutase (SOD) enzyme increased by 150%, 70%, and 30% in activity, and nitric oxide (NO) grew by 409.6%, 212.5%, and 990.4% in content compared with the control at 48 h, 96 h, 168 h. Under cold stress (Cs), ROS increased in the early stage and decreased in the later stage. As key factors responded to Cs, proline (Pro) increased respectively by 285%, 383%, and 81% in content, and heat shock transcriptional factor HSFA1d increased respectively by 161%, 71%, and 204% in transcript level compared with the control at 48 h, 96 h, 168 h. Furthermore, the transcript level of antioxidant enzymes or antioxidant coding genes was consistent with the changing trend of enzymes activity or antioxidant content. Notably, both glutathione (GSH) and heat shock protein 97 (hsp 97) were up-regulated in response to Hs and Cs. In conclusion, GSH and hsp 97 were the core elements of UTEX 2341 in response to both Hs and Cs. SOD and NO were the key elements that responded to Hs, while proline and HSFA1d were the key elements that responded to Cs. This study provided a basis for the understanding of the response mechanism of microalgae under temperature stress and the improvement of the microalgae tolerance to temperature stress. • Glutathione and hsp 97 were the core factors in algae responded to temperature stress. • Proline and HSFA1d were the key factors in algae responded to cold stress. • SOD and NO were the key factors in algae responded to heat stress. • A suggested working model of microalgae for cold/heat-resistance was constructed. [ABSTRACT FROM AUTHOR]

Summary: Gamma‐aminobutyric acid (GABA) and delta‐aminolevulinic acid (ALA), playing important roles in agriculture, medicine and other fields, are multifunctional non‐protein amino acids with similar and comparable properties and biosynthesis pathways. Recently, microbial synthesis has become an inevitable trend to produce GABA and ALA due to its green and sustainable characteristics. In addition, the development of metabolic engineering and synthetic biology has continuously accelerated and increased the GABA and ALA yield in microorganisms. Here, focusing on the current trends in metabolic engineering strategies for microbial synthesis of GABA and ALA, we analysed and compared the efficiency of various metabolic strategies in detail. Moreover, we provide the insights to meet challenges of realizing industrially competitive strains and highlight the future perspectives of GABA and ALA production. [ABSTRACT FROM AUTHOR]

• Cd2+ inhibited the most of basic metabolism pathways except lipid metabolism. • Seven transcription factors with glutathionylated sites linked to TAG metabolism. • Transcription factors MYB, NF-YB and ABI5 regulated DGAT expression. • Triacylglycerol maintained lipid homeostasis by balancing fatty acids saturation. • Microalgae activated TAG synthesis by GSH then resisted the Cd stress together. Under ultra-high cadmium (Cd) stress, large amounts of glutathione are produced in Auxenochlorella protothecoides UTEX 2341, and the lipid content increases significantly. Glutathione is the best reductant that can effectively remove Cd, but the relationship between lipid accumulation and the cellular response to Cd stress has not been ascertained. Integrating analyses of the transcriptomes and lipidomes, the mechanism of lipid accumulation to Cd tolerance were studied from the perspectives of metabolism, transcriptional regulation and protein glutathionylation. Under Cd stress, basic metabolic pathways, such as purine metabolism, translation and pre-mRNA splicing process, were inhibited, while the lipid accumulation pathway was significantly activated. Further analysis revealed that the transcription factors (TFs) and genes related to lipid accumulation were also activated. Analysis of the TF interaction sites showed that ABI5, MYB_rel and NF-YB could further regulate the expression of diacylglycerol acyltransferase through glutathionylation/deglutathionylation, which led to increase of the triacylglycerol (TAG) content. Lipidomes analysis showed that TAG could help maintain lipid homeostasis by adjusting its saturation/unsaturation levels. This study for the first time indicated that glutathione could activate TAG synthesis in microalga A. protothecoides , leading to TAG accumulation and glutathione accumulation under Cd stress. Therefore, the accumulation of TAG and glutathione can confer resistance to high Cd stress. This study provided insights into a new operation mode of TAG accumulation under heavy metal stress. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Koumiss is a slightly alcoholic fermented mare’s milk beverage, originally obtained by using a natural mixed starter of lactic acid bacteria and yeasts. Yeast is an important component of Koumiss processing which can affect the aroma, texture, as well as the nutrients beneficial to human health, but few reports have examined the yeast ecology of local ecosystems. The purpose of this study was to isolate and identify the yeast present in Koumiss from three representative regions of China using a polyphasic method. A total of 655 yeast isolates were obtained from 96 Koumiss samples collected from three regions in China. Koumiss harbored yeast populations at 5–7 log CFU/ml. Twelve different yeast species belonging to nine genera were detected in the Koumiss samples tested, including Candida pararugosa, Dekkera anomala, Geotrichum sp., Issatchenkia orientalis, Kazachstania unispora, Kluyveromyces marxianus, Pichia deserticola, Pichia fermentans, Pichia manshurica, Pichia membranaefaciens, Saccharomyces cerevisiae and Torulaspora delbrueckii. Kluyveromyces marxianus, Kazachstania unispora and Saccharomyces cerevisiae were the dominant species present in this traditional fermented dairy product. This study is the first to identify the yeast communities associated with Koumiss in China. The results enrich our knowledge of yeast in Koumiss, give us a more complete picture of the microbial diversity in Koumiss and can be used to promote the development of the local dairy industry. [Copyright &y& Elsevier]

Abstract: In this study, a novel alkaliphilic extracellular endo-β-1,4-xylanase was purified from the culture filtrate of microbial community EMSD5, which could grow in liquid culture fermentation under static condition with corn stover as inducement. Single step purification was achieved using anion exchange chromatography. The purified enzyme showed a single band on SDS polyacrylamide gel electrophoresis (SDS-PAGE) with an apparent molecular weight of 22kDa and pI of 7.1. Stimulation of the activity by β-mercaptoethanol, and dithiotheritol (DTT) was observed. Moderately thermostable xylanase showed optimum activity at 50°C in pH 8.0. 16S rDNA clone library analysis indicated this community was mainly composed of bacteria related to genera Clostridium, Acinetobacter, Bacteroides, Lysinibacillus and Dysgonomonas. The present work reports for the first time the purification and characterization of an alkaliphilic xylanase from a microbial community, and the alkaliphilicity and moderate thermostability of this xylanase may have potential implications in pulp and paper industries. [Copyright &y& Elsevier]

Abstract: The development of biological processes for fossil energy utilization has received increasing attention in recent years. There are abundance of lignite resources in China and the lignite, a low-grade coal, can be transformed by a Penicillium sp. After fungal transformation, the contents of humic acid and water-soluble humic material increased from 38.6% to 55.1%, and from less than 4.0% to 28.2%, respectively. The differences in chemical properties of crude lignite humic acid (aHA), fungal transformed lignite humic acid (bHA) and water-soluble humic material from fungal transformed lignite (WS) were studied. Elemental analysis and size exclusion chromatography showed that the N content of bHA increased by 47.36% compared with aHA, and the molecular mass of bHA was smaller than aHA. And the WS with the smallest molecular mass contained most content of N. The 13C NMR and FT-IR spectra of aHA and bHA showed that aHA contained more aromatic structure than bHA. [Copyright &y& Elsevier]

Abstract: The iron-deficient culture supernatant of a soil bacterial strain identified as Erwinia sp. was analyzed using a new high-resolution polyamide thin layer chromatography (TLC) and a silica TLC. The results showed both TLC methods were very effective for separating simple catechol compounds such as 2,3-dihydroxybenzoic acid (2,3-DHBA) and catechol. However, in the analysis of more complicated catechol compounds or true catechol-type siderophores (conjugates of 2,3-DHBA and amino acids), the polyamide TLC had the higher resolution. Polyamide TLC analysis showed that strain S1 produced three distinct catechol-type siderophores. [Copyright &y& Elsevier]

Background: Both APETALA2/Ethylene Responsive Factor (AP2/ERF) superfamily and R2R3-MYB family were from one of the largest diverse families of transcription factors (TFs) in plants, and played important roles in plant development and responses to various stresses. However, no systematic analysis of these TFs had been conducted in the green algae A. protothecoides heretofore. Temperature was a critical factor affecting growth and lipid metabolism of A. protothecoides. It also remained largely unknown whether these TFs would respond to temperature stress and be involved in controlling lipid metabolism process. Results: Hereby, a total of six AP2 TFs, six ERF TFs and six R2R3-MYB TFs were identified and their expression profiles were also analyzed under low-temperature (LT) and high-temperature (HT) stresses. Meanwhile, differential adjustments of lipid pathways were triggered, with enhanced triacylglycerol accumulation. A co-expression network was built between these 18 TFs and 32 lipid-metabolism-related genes, suggesting intrinsic associations between TFs and the regulatory mechanism of lipid metabolism. Conclusions: This study represented an important first step towards identifying functions and roles of AP2 superfamily and R2R3-MYB family in lipid adjustments and response to temperature stress. These findings would facilitate the biotechnological development in microalgae-based biofuel production and the better understanding of photosynthetic organisms' adaptive mechanism to temperature stress. [ABSTRACT FROM AUTHOR]

Influence of water content on the expression of lignocellulolytic enzymes by Phanerochaete chrysosporium remains unclear. This work compares the enzyme production profiles of P. chrysosporium during solid-state and submerged fermentation. There were 110 and 64 extracellular carbohydrate-active enzymes identified in solid-state and submerged fermentation respectively, among which 57 enzymes were common to both of the secretomes. P. chrysosporium secreted more cellulases (especially lytic polysaccharide monooxygenase) and hemicellulases during solid-state fermentation while the proportion of enzyme containing carbohydrate-binding module was higher for submerged fermentation. Although its activities were weaker, the enzyme cocktail from submerged fermentation was surprisingly more effective in hydrolysis at low substrate loading. This advantage of enzymes from submerged fermentation was mainly attributed to carbohydrate-binding module because more xylanases bound with substrate at the beginning of hydrolysis. These results reveal the influence of fermentation conditions on enzyme produced by P. chrysosporium for the first time and show the importance of carbohydrate-binding module in the hydrolysis process of lignocellulose. • Secrotomes of Phanerochaete chrysosporium under SSF and SmF were compared. • P. chrysosporium secreted more kinds of enzyme with higher activities under SSF. • Enzyme cocktail from SmF was more effective in hydrolysis at low substrate loading. • Advantage of enzymes from SmF in hydrolysis was mainly attributed to more CBMs. [ABSTRACT FROM AUTHOR]

Raffinose family oligosaccharides (RFOs) negatively affect nutritional value of legume-derived food and feed. It has been challenging to develop a high performance α-galactosidase excelled on catalytic efficiency, thermostability, pH stability and protease-resistance that could efficiently hydrolyze RFOs. In this study, the first GH family 27 α-galactosidase gene from Irpex lacteus was cloned. The gene had an open reading frame of 1314 bp interrupted by 12 introns. The recombinant α-galactosidase expressed in Pichia pastoris (rILgalA) had an apparent molecular mass of 64 kDa and was highly N-glycosylated. rILgalA was maximally active at pH 4.8 and 70 °C. It was stable over a broad pH range of 3–11, retained 90% of its activity after incubation at 60 °C for 10 h and exhibited strong resistance to digestive proteases. Unlike many other α-galactosidases, rILgalA was hyperactive on RFOs. Its specific activities toward melibiose, raffinose and stachyose were 644, 755 and 833 U mg−1, respectively. The corresponding K cat / K m values were 120, 130 and 180 mM−1 s−1, which were the highest among reported α-galactosidases. rILgalA almost completely hydrolyzed raffinose and stachyose in soymilk at 60 °C in 30 min. These superior properties would make rILgalA an ideal remover of RFOs in food and feed industries. Unlabelled Image • α-Galactosidase gene from Irpex lacteus was cloned for the first time. • rILgalA expressed in P. pastoris was hyperactive on RFOs. • rILgalA possessed good thermal and pH stability as well as strong protease-resistance. • The rapidest enzymatic removal of RFOs from soymilk was achieved by rILgalA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Distinct pretreated substrate can be used as inducer for specific enzyme production. • Formulation of cocktails with distinct components improved the hydrolysis efficiency. • 100% glucose and xylose of ultrafine grinding treated corn stover were obtained. In order to optimize the composition of enzyme cocktail for improving the hydrolytic efficiency of lignocellulose, different substrates were tested as inducers for producing lignocellulolytic enzymes by Trichoderma harzianum EM0925 in this study. As results, ultrafine grinding or steam explosion pretreated substrates can induce T. harzianum EM0925 to secret holo lignocellulolytic enzymes; acid treated substrate can induce cellobiohydrolase; while alkali or sodium chlorite treated substrates can induce β-xylosidase specifically. Furthermore, the combination of enzyme cocktails with different hydrolysis characteristics can further improve the hydrolysis efficiency, since 100% yields of glucose and xylose were obtained simultaneously from ultrafine grinding treated corn stover at low enzyme dosage (1.2 mg proteins/g substrate). This study for the first time demonstrated an effective solution that specific-pretreated substrates can be used as inducers for specific enzyme production by T. harzianum , which provided new idea and potential strategy for the construction of highly-efficient lignocellulolytic enzyme cocktails. [ABSTRACT FROM AUTHOR]

A composted material derived from biogas production residues, spent mushroom substrate (SMS) and pig manure was evaluated as a partial or total replacement for peat in growth medium for tomato and pepper seedlings. Five different substrates were tested: T1, compost + perlite (5:1, v:v); T2, compost + peat + perlite (4:1:1, v:v:v); T3, compost + peat + perlite (2.5:2.5:1, v:v:v); T4, compost + peat + perlite (1:4:1, v:v:v); and CK, a commercial peat + perlite (5:1, v:v). The physical-chemical characteristics of the various media were analyzed, and the germination rate and morphological growth were also measured. Real-time Quantitative PCR (qPCR) was used to quantify Fusarium concentrations. The addition of compost to peat-based growth medium increased the pH, electrical conductivity, air porosity, bulk density, and nutrition (NPK), and decreased the water holding capacity and total porosity. The use of compost did not affect the percent germination at day 15 of the tomato and pepper seedlings. The addition of compost resulted in better or comparable seedling quality compared with CK and fertilized CK. The best growth parameters were seen in tomato and pepper seedlings grown in T1 and T2, with higher morphological growth in comparison with CK and fertilized CK. However, T2 showed the highest Fusarium concentration compared to compost and all growth media. Fusarium concentrations in T1, T3, and T4 did not differ significantly from those in CK for tomato seedlings, and those in T1 and T4 were also similar to those in CK for pepper seedlings. The results suggest that biogas residues and SMS compost is a good alternative to peat, allowing 100% replacement, and that 20–50% replacement produces tomato and pepper seedlings with higher morphological growth and lower Fusarium concentrations. [ABSTRACT FROM AUTHOR]

Herein, we report the secretome of Penicillium chrysogenum P33 under induction of lignocellulose for the first time. A total of 356 proteins were identified, including complete cellulases and numerous hemicellulases. Supplementing a commercial cellulase with increasing dosage of P33 enzyme cocktail from 1 to 5 mg/g substrate increased the release of reducing sugars from delignified corn stover by 21.4% to 106.8%. When 50% cellulase was replaced by P33 enzyme cocktail, release of reducing sugars was 78.6% higher than with cellulase alone. Meanwhile, glucan and xylan conversion was increased by 37% and 106%, respectively. P33 enzyme cocktail also enhanced commercial cellulase hydrolysis against four different delignified lignocellulosic biomass. These findings demonstrate that mixing appropriate amount of P33 cocktail with cellulase improves polysaccharide hydrolysis, suggesting P33 enzymes have great potential for industrial applications. [ABSTRACT FROM AUTHOR]

In this study, lignite was degraded using a purified esterase from Penicillium decumbens P6 for the first time. The esterase was purified using ammonium sulfate precipitation, anion exchange and gel filtration chromatography. The recovery and purification yield of the enzyme were 15% and 83 folds, respectively. The molecular weight of the purified enzyme was about 45 kDa. Both crude and purified esterases were studied for lignite depolymerization. The tendency of depolymerization by crude enzyme was consistent with the enzyme secreted in the medium. Along with the increased purified esterase concentration from 8 to 50 mg/ml, A 450 value increased from 0.38 to 2.08. The contribution of esterase to the depolymerization was about 40% in the crude supernatant. Compared with aHA (crude lignite humic acid), bHA (esterase degraded lignite humic acid) has a lower percentage of aromatic carbon and ester groups, but a higher percentage of aliphatic carbon. bHA can promote the growth of asparagus lettuce. The results demonstrated that lignite was depolymerized by the purified esterase and evidenced the potential of esterase application in conversion of lignite into compounds with high bioactivities. [ABSTRACT FROM AUTHOR]

Optimization of the composition of enzyme cocktail is an effective way to improve the hydrolytic efficiency and reduce the cost during enzymatic hydrolysis of lignocellulose. Herein, the optimal enzymes ratios of enzyme cocktails for efficient hydrolysis of corncobs with distinct pretreatments were quantitatively formulated. As the importance of pretreatment type on xylan extraction, the optimized cellulase/hemicellulase ratios for NaClO 2 , H 2 SO 4 and steam explosion treated corncob were 1:1.5, 1:0.15 and 1:0.75, respectively. Meanwhile, different requirements for types of cellulases are also determined: endoglucanase and cellobiohydrolase were key enzymes in the hydrolysis of NaClO 2 and H 2 SO 4 treated corncobs, respectively, while the synergy of three kinds of cellulases was preferred for steam-exploded corncob. Furthermore, based on the optimized cellulase/hemicellulase ratios, cellulases proportions for hydrolyzing the corncobs pretreated with distinctive methods were determined. Notably, by the enzymatic formulation strategy, 100% yields of glucose and xylose were obtained simultaneously from NaClO 2 treated corncob, which was up to 70.1% and 80.1% at high solid loading (20%), respectively. Without detoxification of hydrolysate, high isopropanol yield of 0.45 g/g (of dry matter) was achieved. Hence, this study demonstrated a low cost and high efficient conversion strategy for prospective high-value utilization of lignocellulose. • Three pretreatments for lignin and hemicellulose extraction were tested. • Key enzymes for hydrolyzing corncobs with distinct pretreatments were analyzed. • 100% glucose and xylose of sodium chlorite treated corncob were obtained. • Maximum corncob biomass conversion to biofuels was unlocked. [ABSTRACT FROM AUTHOR]

A series of N , N -3-phenyl-3-benzylaminopropanamide derivatives were identified as novel CETP (cholesteryl ester transfer protein) inhibitors. In our previous study, lead compound L10 was discovered by pharmacophore-based virtual screening (Dong-Mei Zhao et al., 2014). Based on L10 (IC 50 8.06 μM), compound HL6 (IC 50 10.7 μM) was discovered following systematic structure variation and biological tests. Further optimization of the structure–activity relationship (SAR) resulted in N , N -3-phenyl-3-benzylaminopro panamides derivatives as novel CETP inhibitors. They were synthesized and evaluated against CETP by BODIPY-CE fluorescence assay. Among them, HL16 (IC 50 0.69 μM) was a highly potent CETP inhibitor in vitro. In addition, HL16 exhibited favorable HDL-C enhancement and LDL-C reduction in vivo by hamster. The molecular docking of HL16 into the CETP was performed. The binding mode demonstrated that HL16 occupied the CETP binding site and formed interactions with the key amino acid residues. [ABSTRACT FROM AUTHOR]

Stevioside is a non-caloric, natural, high-intensity sweetener. However, the bitter aftertaste of stevioside restricts its utilization for human consumption and limits its application in the food industry. In this study, a high efficiency enzymatic modification system was investigated to improve stevioside taste quality. A cyclodextrin glucanotransferase (CGTase) producing strain Paenibacillus sp. CGMCC 5316 was isolated from Stevia planting soil. With starch as glycosyl donor, this CGTase can transform stevioside into a single specific product which is an isomer of rebaudioside A and identified as mono-glycosylated stevioside . The taste of stevioside is improved noticeably by generating mono-glycosylated stevioside, which possesses a sucrose-like taste and has sweetness increased significantly by 35.4 %. Next, the parameters influencing CGTase production were optimized. Compared to initial conditions, CGTase activity increased by 214.7 % under optimum conditions of 3.9 g/L starch, 17.9 g/L tryptone, and 67.6 h of culture time, and the transglycosylation rate of stevioside was remarkably increased by 284.8 %, reaching 85.6 %. This CGTase modification system provides a promising solution for improving the sweetness and taste quality of stevioside. The efficiency of CGTase transformation can be greatly increased by optimizing the culture conditions of Paenibacillus sp. CGMCC 5316. [ABSTRACT FROM AUTHOR]

In recent years, yak milk has received widespread attention due to its high nutrition, green and pollution-free characteristics, but the source of yak milk flavor is still unclear. In this study, fresh yak manure collected from Lhasa, Nagqu, Qamdo, Yushu, and Qinghai Lake were sequenced by 16S rRNA gene high-throughput sequencing technology. The correlation between intestinal microbiota and yak milk quality combined with the local environmental factors was evaluated for the first time. The enterotype of yaks from Lhasa, Nagqu, and Qinghai Lake was classified as enterotype of norank_f_Oscillospirales_UCG-010 and Rikenellaceae_ RC9_gut_group , and the enterotype of yaks from Qamdo and Yushu was classified as enterotype of Oscillospiraceae UCG-005. Procrustes analysis showed that there was a close relationship between yak milk composition and intestinal microbiota. Metabolic pathway analysis found that different genera and key enzymes of methane and short-chain fatty acid metabolic pathways differed in their responses to environmental factors. Based on the above analysis, a model about environmental factors, intestinal bacteria and the flavor of yak milk was developed. The results provided a reference for the study of flavor substances in yak milk and a new direction for the improvement of dairy products and their derivatives. • The yak gut microbial diversity of southeastern Tibet-Qinghai Plateau is studied. • The yak is divided into Enterotype 1 and Enterotype 2 according to its gut microbes. • Stable enterotype is the basis for the function of different genera in the gut. • Yak milk flavor is closely related to gut microbes and local environmental factors. • A model based on enterotype to influence the flavor of yak milk is constructed. [ABSTRACT FROM AUTHOR]

Microalgae are the largest CO 2 fixer and O 2 producer on the earth and occupy an increasingly important position in human life and production. Various environmental factors have a significant impact on the growth and metabolism of microalgae. As global warming intensifies, heat stress has become a crucial factor affecting the microalgae industry. However, till now, it has not been clear how microalgae sensed the temperature stress, transmitted stress signals and adjusted in intracellular metabolic pathways. In this study, the growth of microalgae Auxenochlorella protothecoides UTEX2341 was inhibited at 32 °C, but the single cell dry weight increased. The cell component analyses showed that both the carbohydrate and total protein content decreased significantly, while the lipid content increased by 158%. Meanwhile, the intracellular Ca2+ concentration increased continuously, with a maximum increase of 1.65 times. According to the transcriptome analyses, the up-regulation of Ca2+ influx channel protein mid1-complementing activity 1 (MCA1) gene and the down-regulation of efflux channel protein cation exchanger 1(CAX) and autoinhibited Ca2+-ATPase 1 (ACA1) genes in cytoplasmic membrane jointly facilitated the increase of Ca2+ in the cytoplasm. Coexpression network analysis indicated that the fluctuation of Ca2+ in the cytoplasm could activate the expression of transcription factors MYB3 and AP2-4 through calmodulin (CAM) and calcium-dependent protein kinase (CDPK), and then regulate glycerol-3-phosphate acyltransferases (GPAT) at the beginning of TAG synthesis and diacylglycerol acyltransferase (DGAT)/phospholipid: diacylglycerol acyltransferase (PDAT) in the last step of TAG synthesis. Furthermore, the addition of Ca2+ specific chelator BAPTA-AM inhibited the expression of GPAT , which was consistent with the decrease in microalgae lipid content. The results proved that Ca2+ participated in the regulation of microalgae TAG synthesis under heat stress, which provided a new view for the understanding of the microalgae lipid accumulation mechanism. [Display omitted] • Heat stress was transmitted to microalgae through Ca2+. • MCA1 channel protein was the valve of Ca2+ influx under heat stress. • Ca2+ influx was the internal cause of the TAG accumulation increase. [ABSTRACT FROM AUTHOR]

Phosphate accumulating bacterium Pseudomonas stutzeri YG-24 exhibited efficient heterotrophic nitrification and aerobic denitrification ability. Single factor experiments showed that both heterotrophic nitrification and aerobic denitrification occurred with sodium citrate as carbon source and lower C/N ratio of 8. High average NH 4 + -N, NO 2 − -N and NO 3 − -N removal rates of 8.75, 7.51 and 7.73 mg L −1 h −1 were achieved. The application of strain YG-24 in wastewater samples resulted in TN, NH 4 + -N, NO 2 − -N, NO 3 − -N and P removal efficiencies of 85.28%, 88.13%, 86.15%, 70.83% and 51.21%. Sequencing and quantitative amplification by real-time PCR of napA , nirS and ppk showed that nitrogen removal pathway of strain YG-24 was achieved through heterotrophic ammonium nitrification coupled with fast nitrite denitrification (NH 4 + -N to NO 2 − -N and then to gaseous nitrogen) directly. These results demonstrated the strain as a suitable candidate to simultaneously remove both nitrogen and phosphate in wastewater treatment. [ABSTRACT FROM AUTHOR]

Algae lipid production combined with heavy metal removal is a cost-effective and environment-friendly method for algae biofuel production and hazardous waste treatment. Chlorella minutissima UTEX 2341 had strong resistance to cadmium, copper, manganese and zinc ions under heterotrophic culture condition and could efficiently remove them through intracellular accumulation and extracellular immobilization. Meanwhile, lipid accumulation was not inhibited by heavy metals. Instead, the algae lipid content significantly increased by 21.07% and 93.90%, respectively with the addition of cadmium and copper. Furthermore, the heavy metal residue in lipid was within μg range and satisfied the commercial standard. This artificial wastewater-algae biofuel-heavy-metal integrated utilization technology offered a new alternative solution to the problems of energy shortage and environmental pollution. [ABSTRACT FROM AUTHOR]

Highlights: [•] An EFS model to deal with large quantities of cow wastewater was explored. [•] A novel complex microbial agent was developed for wastewater treatment. [•] A Paenibacillus lactis strain was first reported in the ectopic fermentation system. [ABSTRACT FROM AUTHOR]

Abstract: To reduce the cost of algal biomass production, mathematical model was developed for the first time to describe microalgae growth, lipid production and glycerin consumption under photoheterotrophic conditions based on logistic, Luedeking–Piret and Luedeking–Piret-like equations. All experiments were conducted in a 2L batch reactor without considering CO2 effect on algae’s growth and lipid production. Biomass and lipid production increased with glycerin as carbon source and were well described by the logistic and Luedeking–Piret equations respectively. Model predictions were in satisfactory agreement with measured data and the mode of lipid production was growth-associated. Sensitivity analysis was applied to examine the effects of certain important parameters on model performance. Results showed that S0, the initial concentration of glycerin, was the most significant factor for algae growth and lipid production. This model is applicable for prediction of other single cell algal species but model testing is recommended before scaling up the fermentation of process. [ABSTRACT FROM AUTHOR]

Abstract: A novel intracellular bioflocculant (named MBF-W6) produced by Chryseobacterium daeguense W6 cultured in low nutrition medium was investigated in this study. The effects of carbon source, nitrogen source, C/N ratio, initial pH, inoculum size, culture temperature and shaking speed on MBF-W6 production were studied. Chemical analysis showed that the purified MBF-W6 was mainly composed of 32.4% protein, 13.1% polysaccharide and 6.8% nucleic acid. Fourier-transform infrared (FTIR) spectroscopy indicated the presence of carboxyl, hydroxyl, and methoxyl groups. The elemental analysis of purified MBF-W6 revealed that the mass proportion of C, H, O, N and S was 40.92:6.53:44.01:8.53:1.01 (w/w) correspondingly. MBF-W6 had good flocculating rate in Kaolin suspension without any cation addition. The highest flocculating rate of 96.9% was achieved under the optimal conditions (bioflocculant dosage 1.2mgl−1, pH 5.6 and temperature 15°C). [Copyright &y& Elsevier]

Abstract: Humic acids (HAs) play an important role in the global nitrogen cycle by influencing the distribution, bioavailability, and ultimate fate of organic nitrogen. Ammonium oxidation by autotrophic ammonia-oxidizing bacteria (AOB) is a key process in ecosystems and is limited, in part, by the availability of NH4 +. We evaluated the impact of HAs on soil AOB in microcosms by applying urea (1.0%, equal to 10 mg urea/g soil) with 0.1% bHA (biodegraded lignite humic acids, equal to 1 mg/g soil), 0.1% cHA (crude lignite humic acids) or no amendment. AOB population size, ammonium and nitrate concentrations were monitored for 12 weeks after urea and HA application. AOB densities (quantified by real-time PCR targeting the amoA) in the Urea treatments increased about ten-fold (the final abundance: 5.02 × 107 copies (g of dry soil)−1) after one week of incubation and decreased to the initial density after 12 weeks incubation; the population size of total bacteria (quantified by real-time PCR with a universal bacterial probe) decreased from 1.12 × 1010 to 2.59 × 109 copies (g of dry soil)−1 at week one and fluctuated back to the initial copy number at week 12. In the Urea + bHA and Urea + cHA treatments, the AOB densities were 4 and 6 times higher, respectively, than the initial density of approximately 5.07 × 106 copies (g of dry soil)−1 at week 1 and did not change much up to week 4; the total bacteria density changed little over time. The AOB and total bacteria density of the controls changed little during the 12 weeks of incubation. The microbial community composition of the Urea treatment, based on T-RFLP using CCA (canonical correspondence analysis) and pCCA (partial CCA) analysis, was clearly different from those of other treatments, and suggested that lignite HAs buffered the change in diversity and quantity of total bacteria caused by the application of urea to the soil. We hypothesize that HAs can inhibit the change in microbial community composition and numbers, as well as AOB population size by reducing the hydrolysis rate from urea to ammonium in soils amended with urea. [Copyright &y& Elsevier]

Abstract: Sugarcane bagasse (SCB) is a residual product of sugar processing, containing mainly lignocellulose. The biodegradation of cellulose is an economical approach to recycling SCB. To obtain an effective microbial community and study the SCB biodegradation process, a SCB-degrading mesophilic microbial community, EMSD13, growing at 50°C was isolated. More than 77% of alkali pretreated SCB was degraded and over 83% of the cellulose it contained was utilized by the EMSD13 community within 6 days. To understand the biodegradation procedure of EMSD13, extracellular and SCB-absorbable cellulases were analyzed. The peak activity (42mU/mL) of the extracellular cellulase in the supernatant occurred on the 3rd day of incubation. About 73.6mg of substrate-bound proteins with a cellulase activity of 61.1mU/mg were recovered from residual SCB by eluting with 3M guanidine hydrochloride. Also, 15.9mg of proteins with 28.6mU/mg of cellulase activity were obtained from residual SCB by eluting with 6M urea. SDS-PAGE analysis showed that cellulases in both elutes were similar, but most differed from those in the supernatant. This is the first report on substrate-bound cellulases from a microbial community. [Copyright &y& Elsevier]

• A novel bifunctional xylanase/feruloyl esterase (rXyn10A/Fae1A) was obtained. • The highest ferulic acid yield (7.31 mg/g substrate) was produced by rXyn10A/Fae1A. • Inter-domain synergism of rXyn10A/Fae1A is essential for the release of ferulic acid. • Recombinant E. coli was constructed and secreted the bifunctional enzyme out of cells. • Co-production of ferulic acid and XOSs during the cultivation of recombinant E. coli. Liberating high value-added compounds ferulic acid (FA) and xylo-oligosaccharides (XOSs) from agricultural residues is a promising strategy for the utilization of lignocellulose. In this study, a bifunctional xylanase/feruloyl esterase from bacterial consortium EMSD5 was heterogeneously expressed in Escherichia coli. Depending on the inter-domain synergism of the recombinant enzyme rXyn10A/Fae1A, high yields of FA (2.78, 1.82, 1.15 and 7.31 mg/g substrate, respectively) were obtained from 20 mg in-soluble wheat arabinoxylan, de-starched wheat bran, ultrafine-grinding corn stover and steam-exploded corncob. Meanwhile, 3.210, 1.235, 1.215 and 0.823 mg xylose/XOSs were also released. For cost-saving enzyme production, we firstly constructed a recombinant E. coli , which could secrete the bifunctional xylanase/feruloyl esterase out of cells. When the recombinant E. coli was cultured in medium containing 200 mg de-starched wheat bran, 474 μg FA and 18.2 mg xylose/XOSs were also detected. Hence, rXyn10A/Fae1A and the recombinant strain showed great applied potential for FA and XOSs production. [ABSTRACT FROM AUTHOR]

• Bacterial consortium EMSD5 produced isopropanol from xylans efficiently. • 7.00 g/L isopropanol was produced from unpretreated corncob by consortia-based CBP. • Arabinose residues of xylan could enhance the CBP performance. • Clostridium beijerinckii and lignocellulose degraders performed CBP synergistically. Consolidated bioprocessing (CBP) of lignocellulose by bacterial consortium for isopropanol production is considered as the most promising strategy. However, low utilization of xylan caused by the complex sidechain structure remains inhibit the conversion of full-biomass. In this study, isopropanol production from different lignocelluloses by the consortium EMSD5 through CBP was performed. A total of 7.00 g/L of isopropanol was obtained from corncob by optimizing fermentation conditions. Isopropanol production by EMSD5 was mainly based on utilizing xylan in corncob and isopropanol titer was increased by 47.71% and reached up to 8.39 g/L using arabinoxylan compared with linear xylan. The analysis of community structures and the isolation of key strain confirmed the enrichment of the isopropanol producer, Clostridium beijierinckii , in the bacterial community when it was incubated with corn glucuronoarabinoxylan and the cooperation between C. beijerinckii and lignocellulose degraders. The unique features of EMSD5 could lead to large-scale isopropanol production using lignocellulose. [ABSTRACT FROM AUTHOR]

Background: Xylanases randomly cleave the internal β-1,4-glycosidic bonds in the xylan backbone and are grouped into different families in the carbohydrate-active enzyme (CAZy) database. Although multiple xylanases are detected in single strains of many filamentous fungi, no study has been reported on the composition, synergistic effect, and mode of action in a complete set of xylanases secreted by the same microorganism. Results: All three xylanases secreted by Penicillium chrysogenum P33 were expressed and characterized. The enzymes Xyl1 and Xyl3 belong to the GH10 family and Xyl3 contains a CBM1 domain at its C-terminal, whereas Xyl2 belongs to the GH11 family. The optimal temperature/pH values were 35 °C/6.0, 50 °C/5.0 and 55 °C/6.0 for Xyl1, Xyl2, and Xyl3, respectively. The three xylanases exhibited synergistic effects, with the maximum synergy observed between Xyl3 and Xyl2, which are from different families. The synergy between xylanases could also improve the hydrolysis of cellulase (C), with the maximum amount of reducing sugars (5.68 mg/mL) observed using the combination of C + Xyl2 + Xyl3. Although the enzymatic activity of Xyl1 toward xylan was low, it was shown to be capable of hydrolyzing xylooligosaccharides into xylose. Xyl2 was shown to hydrolyze xylan to long-chain xylooligosaccharides, whereas Xyl3 hydrolyzed xylan to xylooligosaccharides with a lower degree of polymerization. Conclusions: Synergistic effect exists among different xylanases, and it was higher between xylanases from different families. The cooperation of hydrolysis modes comprised the primary mechanism for the observed synergy between different xylanases. This study demonstrated, for the first time, that the hydrolysates of GH11 xylanases can be further hydrolyzed by GH10 xylanases, but not vice versa. [ABSTRACT FROM AUTHOR]