Rhizosphere metabolic cross-talk from plant-soil-microbe tapping into agricultural sustainability: Current advance and perspectives.

Rhizosphere interactions from plant-soil-microbiome occur dynamically all the time in the "black microzone" underground, where we can't see intuitively. Rhizosphere metabolites including root exudates and microbial metabolites act as various chemical signalings involving in rhizosphere interactions, and play vital roles on plant growth, development, disease suppression and resistance to stress conditions as well as proper soil health. Although rhizosphere metabolites are a mixture from plant roots and soil microbes, they often are discussed alone. As a rapid appearance of various omics platforms and analytical methods, it offers possibilities and opportunities for exploring rhizosphere interactions in unprecedented breadth and depth. However, our comprehensive understanding about the fine-tuning mechanisms of rhizosphere interactions mediated by these chemical compounds still remain clear. Thus, this review summarizes recent advances systemically including the features of rhizosphere metabolites and their effects on rhizosphere ecosystem, and looks forward to the future research perspectives, which contributes to facilitating better understanding of biochemical communications belowground and helping identify novel rhizosphere metabolites. We also address challenges for promoting the understanding about the roles of rhizosphere metabolites in different environmental stresses.

Effects of general and spinal anesthesia on postoperative rehabilitation in older adults after lower limb surgery: a retrospective cohort study.

Objective: To investigate the effects of perioperative general anesthesia (GA) and spinal anesthesia (SA) on postoperative rehabilitation in elderly patients with lower limb surgery. Methods: This retrospective propensity score-matched cohort study included patients aged 65 years or older who underwent lower limb surgery between January 1, 2020, and May 31, 2023. The GA and SA were selected at the request of the orthopedic surgeon, patient, and their family members. The main outcomes included the incidence of the patient's inability to self-care at discharge, postoperative complications including pulmonary infection, thrombus of lower extremity veins, infection of incisional wound and delirium, length of hospital stay, and incidence of severe pain in the first 2 days postoperatively. Results: In total, 697 patients met the inclusion criteria, and 456 were included in the final analysis after propensity score matching. In the GA and SA groups, 27 (11.84%) and 26 (11.40%) patients, respectively, could not care for themselves at discharge. The incidence rates did not differ between the groups (p = 0.884). In contrast, the incidence of postoperative complications (GA: 10.53% and SA: 4.39%; p = 0.013) and the length of hospital stay (GA: 16.92 ± 10.65 days and SA: 12.75 ± 9.15 days; p < 0.001) significantly differed between the groups. Conclusion: The choice of anesthesia is independent of the loss of postoperative self-care ability in older patients (>65 years) and is not a key factor affecting postoperative rehabilitation after lower limb surgery. However, compared with GA, SA reduces the incidence of postoperative complications and a prolonged hospital stay. Thus, SA as the primary anesthetic method is a protective factor against a prolonged hospital stay.

Circ_0010235 confers cisplatin resistance in lung cancer by upregulating E2F7 through absorbing miR-379-5p.

BACKGROUND: Cisplatin (DDP) treatment is one of the most predominant chemotherapeutic strategies for lung cancer patients. Circular RNAs (circRNAs) have been revealed to participate in the chemoresistance in lung cancer. Hence, the role and mechanism of circ_0010235 in cisplatin resistance in lung cancer was investigated. METHODS: Expression levels of circ_0010235, microRNA (miR)-379-5p and E2F transcription factor 7 (E2F7) were analyzed using quantitative reverse transcription PCR (qRT-PCR) and western blot. Cell DDP sensitivity, proliferation, apoptosis, invasion, and migration were detected by cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine (EDU) assay, flow cytometry and western blot, respectively. The binding interaction was verified using dual-luciferase reporter assay. A murine xenograft model was established to investigate effects in vivo. RESULTS: Circ_0010235 was highly expressed in DDP-resistant lung cancer tissues and cells. Knockdown of circ_0010235 elevated DDP sensitivity, constrained proliferation, invasion and migration as well as fostered apoptosis in DDP-resistant lung cancer cells. Moreover, circ_0010235 silencing boosted DDP sensitivity and impeded tumor growth in lung cancer in vivo. Mechanistically, circ_0010235 acted as a sponge for miR-379-5p to elevate the expression of its target E2F7. Rescue experiments showed that miR-379-5p inhibition attenuated circ_0010235 knockdown-evoked reduction on DDP resistance of DDP-resistant cancer cells. In addition, miR-379-5p re-expression elevated DDP sensitivity and suppressed the malignant phenotype of DDP-resistant lung cancer cells through miR-379-5p. CONCLUSION: Circ_0010235 knockdown reduced DDP resistance and tumor growth via miR-379-5p/ E2F7 axis in lung cancer, suggesting an effective therapeutic target for lung cancer patients.

The potential use of Zymomonas mobilis for the food industry.

Zymomonas mobilis is a gram-negative facultative anaerobic spore, which is generally recognized as a safe. As a promising ethanologenic organism for large-scale bio-ethanol production, Z. mobilis has also shown a good application prospect in food processing and food additive synthesis for its unique physiological characteristics and excellent industrial characteristics. It not only has obvious advantages in food processing and becomes the biorefinery chassis cell for food additives, but also has a certain healthcare effect on human health. Until to now, most of the research is still in theory and laboratory scale, and further research is also needed to achieve industrial production. This review summarized the physiological characteristics and advantages of Z. mobilis in food industry for the first time and further expounds its research status in food industry from three aspects of food additive synthesis, fermentation applications, and prebiotic efficacy, it will provide a theoretical basis for its development and applications in food industry. This review also discussed the shortcomings of its practical applications in the current food industry, and explored other ways to broaden the applications of Z. mobilis in the food industry, to promote its applications in food processing.

Potential applications of Zymomonas mobilis in food industry summarized for the first time.Research status of Z. mobilis in food additive synthesis, fermentation applications, and probiotics are discussed in details.Future research perspectives of Z. mobilis in food industry further proposed.

Cellulosic ethanol production by consortia of Scheffersomyces stipitis and engineered Zymomonas mobilis.

BACKGROUND: As one of the clean and sustainable energies, lignocellulosic ethanol has achieved much attention around the world. The production of lignocellulosic ethanol does not compete with people for food, while the consumption of ethanol could contribute to the carbon dioxide emission reduction. However, the simultaneous transformation of glucose and xylose to ethanol is one of the key technologies for attaining cost-efficient lignocellulosic ethanol production at an industrial scale. Genetic modification of strains and constructing consortia were two approaches to resolve this issue. Compared with strain improvement, the synergistic interaction of consortia in metabolic pathways should be more useful than using each one separately. RESULTS: In this study, the consortia consisting of suspended Scheffersomyces stipitis CICC1960 and Zymomonas mobilis 8b were cultivated to successfully depress carbon catabolite repression (CCR) in artificially simulated 80G40XRM. With this strategy, a 5.52% more xylose consumption and a 6.52% higher ethanol titer were achieved by the consortium, in which the inoculation ratio between S. stipitis and Z. mobilis was 1:3, compared with the Z. mobilis 8b mono-fermentation. Subsequently, one copy of the xylose metabolic genes was inserted into the Z. mobilis 8b genome to construct Z. mobilis FR2, leading to the xylose final-consumption amount and ethanol titer improvement by 15.36% and 6.81%, respectively. Finally, various corn stover hydrolysates with different sugar concentrations (glucose and xylose 60, 90, 120 g/L), were used to evaluate the fermentation performance of the consortium consisting of S. stipitis CICC1960 and Z. mobilis FR2. Fermentation results showed that a 1.56-4.59% higher ethanol titer was achieved by the consortium compared with the Z. mobilis FR2 mono-fermentation, and a 46.12-102.14% higher ethanol titer was observed in the consortium fermentation when compared with the S. stipitis CICC1960 mono-fermentation. Furthermore, qRT-PCR analysis of xylose/glucose transporter and other genes responsible for CCR explained the reason why the initial ratio inoculation of 1:3 in artificially simulated 80G40XRM had the best fermentation performance in the consortium. CONCLUSIONS: The fermentation strategy used in this study, i.e., using a genetically modified consortium, had a superior performance in ethanol production, as compared with the S. stipitis CICC1960 mono-fermentation and the Z. mobilis FR2 mono-fermentation alone. This result showed that this strategy has potential for future lignocellulosic ethanol production.

Bioenergy from dairy manure: technologies, challenges and opportunities.

Dairy manure (DM) is a kind of cheap cellulosic biomass resource which includes lignocellulose and mineral nutrients. Random stacks not only leads damage to the environment, but also results in waste of natural resources. The traditional ways to use DM include returning it to the soil or acting as a fertilizer, which could reduce environmental pollution to some extent. However, the resource utilization rate is not high and socio-economic performance is not utilized. To expand the application of DM, more and more attention has been paid to explore its potential as bioenergy or bio-chemicals production. This article presented a comprehensive review of different types of bioenergy production from DM and provided a general overview for bioenergy production. Importantly, this paper discussed potentials of DM as candidate feedstocks not only for biogas, bioethanol, biohydrogen, microbial fuel cell, lactic acid, and fumaric acid production by microbial technology, but also for bio-oil and biochar production through apyrolysis process. Additionally, the use of manure for replacing freshwater or nutrients for algae cultivation and cellulase production were also discussed. Overall, DM could be a novel suitable material for future biorefinery. Importantly, considerable efforts and further extensive research on overcoming technical bottlenecks like pretreatment, the effective release of fermentable sugars, the absence of robust organisms for fermentation, energy balance, and life cycle assessment should be needed to develop a comprehensive biorefinery model.

Irrigating digestate to improve cadmium phytoremediation potential of Pennisetum hybridum.

The bioavailability of heavy metal and growth of hyperaccumulator are key factors controlling the phytoextraction of heavy metal from soil. In this study, the efficacy and potential microbial mechanisms of digestate application in enhancing Cd extraction from soil by Pennisetum hybridum were investigated. The results showed that digestate application significantly promoted the height, tiller number, and biomass yield of Pennisetum hybridum. The application also increased the activities of urease, sucrase, dehydrogenase, available Cd contents of rhizosphere soils (from 2.21 to 2.46 mg kg-1), and the transfer factors of Cd from root to shoot and leaf. Assuming three annual harvests, digestate application would substantially reduce time needed for Pennisetum hybridum to completely absorb Cd from soil-from 15-16 yr-10 yr. Furthermore, the results of microbial community diversity analysis showed that digestate irrigation was more facilitated for the growth of the predominant bacteria, which were Actinobacteria and Chloroflexi at phylum level, and Sphingomonas and Nitrospiraat genus level, which mainly have the functions of promoted plant growth and metal resistance. The results suggested that the enhanced phytoextraction of Cd by Pennisetum hybridum with digestate application might mainly attributed to the increased Cd bio-availability and the enhanced plant growth, indicating that an approach combining digestate and Pennisetum hybridum could be a promising strategy for remediating Cd-contaminated soils.

Geochemical and Mineralogical Characteristics of the Li-Sr-Enriched Coal in the Wenjiaba Mine, Guizhou, SW China.

This paper reports the mineralogical and geochemical compositions of C6 coal in the Late Permian Longtan Formation of the Wenjiaba Mine, Northern Guizhou in southwest (SW) China. The geochemical and mineralogical studies are the basis for the potential recovery of critical metals. The Longtan Formation, which is one of the major coal-bearing strata in SW China, contains dozens of coal seams. C6 coal is the main mineable coal seam in the Wenjiaba Mine and the whole coalfield. Proximate and ultimate analyses, inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence (XRF) spectrometry on trace and major element concentrations, and X-ray diffraction and SEM-EDS analyses were carried out. Results suggest that this anthracite coal is characterized by low ash yield and medium sulfur content. The minerals are mainly composed of clay minerals (kaolinite, chlorite, illite, and mixed-layer illite/smectite), pyrite, and carbonates. Lithium is significantly enriched in C6 coal, with an average of 124 µg/g, and it has a higher concentration in the lower portion of the coal seam than that in the upper one. Strontium is significantly enriched in samples WJB-05 and WJB-06, with concentrations of 3030 and 4580 µg/g, respectively, but it is normal or just slightly enriched in other benches of C6 coal. Additionally, Cu, Nb, and Ta are slightly enriched in the coal. Lithium, dominantly hosted by kaolinite in C6 coals, has a recovery potential. Celestine is one of the major Sr-bearing minerals in C6 coal.

Effects of digestate on biomass of a selected energy crop and soil properties.

BACKGROUND: A large number of digestates have not been fully utilized due to a lack of scientific, reasonable guidance, as well as imperfect technology. Hybrid giant Napier has great potential for use as a type of energy plant. As such, this study investigated the effects of digestate on the growth of a candidate energy crop and examined whether digestate was an ecologically viable means for soil restoration. RESULTS: The results showed that the total yields of all treatment groups receiving irrigation of digestate were higher (5.19-26.00%) than those of the control. The total phosphorus, total potassium, available nitrogen, available phosphorus, and available potassium content of the soil had also increased after digestate application, compared with the control. Urease activities for all treatments increased 15.28 to 69.44% more than that of the corresponding control. Soil dissolved organic matter (DOM) mainly contained humic-like and fulvic-like components through the application of digestate. More fluorescent components were also identified by two-dimensional correlation spectroscopy (2D-COS). These fluorescent components can improve the aromaticity and molecular weight of soil DOM so as to improve soil quality. CONCLUSIONS: Digestate improved not only the aboveground biomass accumulation, but also the chemical properties of the soil, which was an appropriate strategy for restoring soil quality and contributing to the sustainable development of marginal. The long-term impact of digestate application on soil quality will require additional long-term experiments. © 2020 Society of Chemical Industry.

Enrichment of waste sewage sludge for enhancing methane production from cellulose.

Low ability of waste sewage sludge to degrade cellulose is observed due to its less cellulolytic bacteria content. The enrichment of sewage sludge in the absence or presence of carboxymethylcellulose (CMC) was conducted to improve anaerobic digestion (AD) of cellulose in this study. Compared to initial sewage sludge (IS), enriched sludge without CMC addition (ES) displayed 69.81% higher CH4 yield and about 1.7-fold greater anaerobic biodegradation of cellulose. In particular, bacterial and archaeal diversities in samples inoculated with ES were significantly altered, with Ruminiclostridium and Methanobacterium as the predominant genera. Enriched sludge with CMC addition (ESC) displayed enhanced methane production at initial cellulose fermentation but showed no distinct difference compared with the control after incubation 24 days. These findings suggest that enrichment of waste sewage sludge without CMC addition is more beneficial for promoting AD of cellulose, providing a novel insight for efficient energy utilization of lignocellulosic wastes.

Enrichment and Occurrence of Mn in 5-2 Coal from Qinglongsi Coal Mine, Northern Ordos Basin, China.

High concentrations of Mn were observed in 5-2 coal (Jurassic age) from Qinglongsi coal mine in the Northern Ordos Basin. To study the occurrence characteristics and sedimentary environment of the 5-2 coal (3.9 m), 22 samples were collected from a mining face. The test result indicates that the 5-2 coal is in low-ash, high-volatile, very low-sulfur, and bituminous rank, with high inertinite content. The minerals in Jurassic 5-2 coal are composed primarily of kaolinite, siderite, calcite, quartz, pyrite, K-feldspar, and fluorapatite. The Mn element is enriched in the upper part of the 5-2 coal seam with an average of 1243.01 µg/g, which is about 17.5 times higher than the average of world hard coal. The concentration level of Mn has a positive correlation with that of Fe2O3 and carbonate minerals. A weak reduction environment of the coal-accumulating swamp may induce the enrichment of Mn, which is mainly carried by siderite in the 5-2 coal.

Replacing water and nutrients for ethanol production by ARTP derived biogas slurry tolerant Zymomonas mobilis strain.

BACKGROUND: Reducing fresh water consumption and nutrient addition will be an effective way to reduce the whole cost of bioethanol production. On the other hand, treatment of biogas slurry derived from anaerobic digestion (AD), in which a great amount of nutrients is still left, costs too much to remove these pollutants. It would be beneficial for both digestate valorization and ethanol production if biogas slurry is used for producing bioethanol. However, both hyperosmosis and potential biotoxic components of the biogas slurry can severely inhibit fermentation. RESULTS: In this study, two rounds of atmospheric and room temperature plasma (ARTP) mutagenesis combined with adaptive laboratory evolution (ALE) were applied to improve the adaptability and genetic stability of Zymomonas mobilis in biogas slurry. Mutants D95 and S912 were identified. Growth of the mutants was remarkably improved in biogas slurry. The highest ethanol productivity reached 0.63 g/L/h which was 61.7% higher than ZM4 (0.39 g/L/h). Genomic re-sequencing results also revealed that single nucleic variations (SNVs) and Indels occurred in the mutants, which are likely related to inhibitor in biogas slurry and low pH tolerance. CONCLUSIONS: Our study demonstrated that these mutant strains have great potential to produce ethanol using biogas slurry to replace fresh water and nutrients.

Engineered Zymomonas mobilis tolerant to acetic acid and low pH via multiplex atmospheric and room temperature plasma mutagenesis.

BACKGROUND: Cellulosic biofuels are sustainable compared to fossil fuels. However, inhibitors, such as acetic acid generated during lignocellulose pretreatment and hydrolysis, would significantly inhibit microbial fermentation efficiency. Microbial mutants able to tolerate high concentration of acetic acid are needed urgently to alleviate this inhibition. RESULTS: Zymomonas mobilis mutants AQ8-1 and AC8-9 with enhanced tolerance against acetic acid were generated via a multiplex atmospheric and room temperature plasma (mARTP) mutagenesis. The growth and ethanol productivity of AQ8-1 and AC8-9 were both improved in the presence of 5.0-8.0 g/L acetic acid. Ethanol yield reached 84% of theoretical value in the presence of 8.0 g/L acetic acid (~ pH 4.0). Furthermore, a mutant tolerant to pH 3.5, named PH1-29, was generated via the third round of ARTP mutagenesis. PH1-29 showed enhanced growth and ethanol production under both sterilized/unsterilized conditions at pH 4.0 or 3.5. Intracellular NAD levels revealed that mARTP mutants could modulate NADH/NAD+ ratio to respond to acetic acid and low pH stresses. Moreover, genomic re-sequencing revealed that eleven single nucleic variations (SNVs) were likely related to acetic acid and low pH tolerance. Most SNVs were targeted in regions between genes ZMO0952 and ZMO0956, ZMO0152 and ZMO0153, and ZMO0373 and ZMO0374. CONCLUSIONS: The multiplex mutagenesis strategy mARTP was efficient for enhancing the tolerance in Z. mobilis. The ARTP mutants generated in this study could serve as potential cellulosic ethanol producers.

Calcium-rich biochar from crab shell: An unexpected super adsorbent for dye removal.

Adsorption is the common-used method to remove dyes from wastewater, and many efforts have been made to develop low-cost but excellent adsorbents. Here, calcium-rich biochar (CRB) as a low-cost adsorbent was directly prepared from crab shell via a simple pyrolysis process without any modification. Batch adsorption results suggested that CRB was among the dye adsorbents with highest adsorption capacities and fastest adsorption rate. Specifically, it showed high adsorption capacities of 12,502 and 20,317 mg/g for cationic malachite green and anionic Congo red, respectively. The adsorption equilibrium for Congo red onto CRB could be achieved as short as 2 min. Furthermore, the dye adsorption mechanism for CRB, as investigated by zeta potential and FTIR spectra, could be attributed to electrostatic attraction, hydrogen bonding and π-π interaction. Finally, this study suggested that, attributed to its cheap source, simple synthesis process and excellent adsorption performance, CRB was promising in dye removal.

Replacing process water and nitrogen sources with biogas slurry during cellulosic ethanol production.

BACKGROUND: Environmental issues, such as the fossil energy crisis, have resulted in increased public attention to use bioethanol as an alternative renewable energy. For ethanol production, water and nutrient consumption has become increasingly important factors being considered by the bioethanol industry as reducing the consumption of these resources would decrease the overall cost of ethanol production. Biogas slurry contains not only large amounts of wastewater, but also the nutrients required for microbial growth, e.g., nitrogen, ammonia, phosphate, and potassium. Therefore, biogas slurry is an attractive potential resource for bioethanol production that could serve as an alternative to process water and nitrogen sources. RESULTS: In this study, we propose a method that replaces the process water and nitrogen sources needed for cellulosic ethanol production by Zymomonas mobilis with biogas slurry. To test the efficacy of these methods, corn straw degradation following pretreatment with diluted NaOH and enzymatic hydrolysis in the absence of fresh water was evaluated. Then, ethanol fermentation using the ethanologenic bacterial strain Z. mobilis ZMT2 was conducted without supplementing with additional nitrogen sources. After pretreatment with 1.34% NaOH (w/v) diluted in 100% biogas slurry and continuous enzymatic hydrolysis for 144 h, 29.19 g/L glucose and 12.76 g/L xylose were generated from 30 g dry corn straw. The maximum ethanol concentration acquired was 13.75 g/L, which was a yield of 72.63% ethanol from the hydrolysate medium. Nearly 94.87% of the ammonia nitrogen was depleted and no nitrate nitrogen remained after ethanol fermentation. The use of biogas slurry as an alternative to process water and nitrogen sources may decrease the cost of cellulosic ethanol production by 10.0-20.0%. By combining pretreatment with NaOH diluted in biogas slurry, enzymatic hydrolysis, and ethanol fermentation, 56.3 kg of ethanol was produced by Z. mobilis ZMT-2 through fermentation of 1000 kg of dried corn straw. CONCLUSIONS: In this study, biogas slurry replaced process water and nitrogen sources during cellulosic ethanol production. The results suggest that biogas slurry is a potential alternative to water when pretreating corn straw and, thus, has important potential applications in cellulosic ethanol production from corn straw. This study not only provides a novel method for utilizing biogas slurry, but also demonstrates a means of reducing the overall cost of cellulosic ethanol.

High-efficiency bioconversion of kitchen garbage to biobutanol using an enzymatic cocktail procedure.

Research on methods to produce biobutanol production from kitchen garbage (KG) as a potential substrate is thus far lacking. Here, the effect of various enzymatic hydrolysis procedures (EHP) was first tested using different enzyme cocktails, on the decomposition of KG. The efficiency of Clostridium acetobutylicum-mediated biobutanol production was then measured using two modes: separate hydrolysis and fermentation (SHF) and simultaneous saccharification fermentation (SSF) in the condition of adjusting pH. The optimal results were obtained using (1) an enzymatic hydrolysis cocktail procedure (EHC5), (2) use of the SSF approach and (3) pH control. This approach results in a biobutanol production of 16.37g/L and total solvent concentration of 32.96g/L. Compared to experiments that use pure glucose asa substrate, our results show that KG is a promising feedstock for biobutanol production. The results demonstrate the feasibility of this waste source for an industrial application via the EHP.

A synergistic combination of nutrient reclamation from manure and resultant hydrochar upgradation by acid-supported hydrothermal carbonization.

Cattle manure was hydrothermally carbonized in acid solutions (0-2% HCl), then nutrient concentration in liquid product and physicochemical properties of hydrochar were characterized to investigate the effects of acid addition on hydrochar properties and nutrient recovery from manure. Results showed that hydrothermal carbonization (HTC) in 2% HCl extracted almost 100% and 63.38% of phosphorus and nitrogen, respectively; specifically, >90% of the extracted phosphorus was PO4-P in liquid from HTC with acid addition, and increasing amount of extracted nitrogen was NH4-N with increasing acid addition. Generally, higher heating value, surface area, total pore volume, fixed carbon, atomic ratios of H/C and O/C were increased in hydrochars from HTC with acid addition, while yield, volatile matter, contents of nitrogen, sulfur and oxygen of these hydrochars were decreased. These results indicated that HTC with acid addition could simultaneously facilitate nutrient recovery from manure and resulting hydrochar upgradation.

Engineering Brevibacterium flavum for the production of renewable bioenergy: C4-C5 advanced alcohols.

Biosynthesis of advanced biofuels by engineered non-natural microorganisms has been proposed to be the most promising approach for the replacement of dwindling fossil fuel resources. Brevibacterium flavum (Bf) is a model brevibacterium aerobe which lacks basic and applied research that could enable this species to produce biofuels. There are no reports regarding engineering this microorganism to produce advanced alcohols before. Here, for the first time, we developed the bacterium as a novel biosynthetic platform for advanced alcohols production via the mutagenesis and engineering to produce 2-ketoacids derived alcohols. In order to enhance the strain's capability of producing advanced alcohols, we preferentially improved intrinsic metabolism ability of the strain to obtain improved expression host (IEH) via generating mutagenesis libraries by whole cell mutagenesis (WCM). The IEH was determined via screening out the mutant strain with the highest production of branched-chain organic acids (BCOA) using high throughput screening method.. Subsequently, a novel vector system for Bf was established, and the corresponding biosynthetic pathway of directing carbon flux into the target advanced alcohols was recruited to make the bacterium possess the capability of producing advanced alcohols and further enhance the production using the IEH. Specifically, we generated bioengineered strains that were able to synthesize up to the highest 5362 and 4976 mg/L isobutanol, 1945 and 1747 mg/L 2-methyl-1-butanol (2 MB), and 785.34 and 781 mg/L 3-methyl-1-butanol (3 MB) from pure glucose and duckweed substrates, respectively. Our findings confirmed the feasibility and potential of using Bf as a novel biosynthetic platform to generate advanced biofuels with glucose and inexpensive renewable feedstock-duckweed as a fermentation substrate. Biotechnol. Bioeng. 2017;114: 1946-1958. © 2017 Wiley Periodicals, Inc.

Calcium-rich biochar from the pyrolysis of crab shell for phosphorus removal.

Calcium-rich biochars (CRB) prepared through pyrolysis of crab shell at various temperatures were characterized for physicochemical properties and P removal potential. Elemental analysis showed that CRB was rich in calcium (22.91%-36.14%), while poor in carbon (25.21%-9.08%). FTIR, XRD and TG analyses showed that calcite-based CRB was prepared at temperature ≤600 °C, while lime-based CRB was prepared at temperature ≥700 °C. Phosphorus removal experiment showed that P removal efficiencies in 80 mg P/L phosphate solution and biogas effluent ranged from 26% to 11%, respectively, to about 100% and 63%, respectively, depending on the pyrolysis temperature of the resulting biochar. Specifically, compared to common used CaCO3 and Ca(OH)2, P removal potential of calcite-based CRB was much higher than that of CaCO3; while that of lime-based CRB was close to that of Ca(OH)2. These results suggested that CRB was competent for P removal/recovery from wastewater.

Investigation of availability of a high throughput screening method for predicting butanol solvent -producing ability of Clostridium beijerinckii.

BACKGROUND: Currently, efficient screening methods for selection of desired bacterial phenotypes from large populations are not easy feasible or readily available due to the complicated physiological and metabolic networks of solventogenic clostridia. In this study, to contribute to the improvement of methods for predicting the butanol-producing ability of Clostridium beijerinckii based on starch substrate, we further investigate a simple, visualization screening method for selecting target strains from mutant library of Clostridium beijerinckii NCIMB 8052 by using trypan blue dye as an indicator in solid starch via statistical survey and validation of fermentation experiment with controlling pH. RESULTS: To verify an effective, efficient phenotypic screening method for isolating high butanol-producing mutants, the revalidation process was conducted based on Trypan Blue was used for visualization, and starch was used as the bacterial metabolic substrate. The availability of the screening system was further evaluated based on the relationship between characteristics of mutant strains and their α-amylase activities. Mutant clones were analyzed in detail based on their distinctive growth patterns and rate of fermentation of soluble starch to form butanol and were compared by statistical method. Significant correlations were identified between colony morphology and changes in butanol concentrations. The screening method was validated via statistical analysis for characterizing phenotypic parameters. The fermentation experiment of mutant strains with controlling pH value also demonstrated a positive correlation between increased α-amylase activity and increased solvent production by Clostridium beijerinckii was observed, and therefore indicated that the trypan blue dyeing method can be used as a fast method to screen target mutant strain for better solvent producers from, for instance, a mutant library. CONCLUSIONS: The suitability of the novel screening procedure was validated, opening up a new indicator of approach to select mutant solventogenic clostridia with improved fermentation of starch to increase butanol concentrations. The applicability can easily be broadened to a wide range of interesting microbes such as cellulolytic or acetogenic microorganisms, which produce biofuels from feedstock rich in starch.