Mitigation of drought-induced stress in sunflower (Helianthus annuus L.) via foliar application of Jasmonic acid through the augmentation of growth, physiological, and biochemical attributes.

Drought stress poses a significant threat to agricultural productivity, especially in areas susceptible to water scarcity. Sunflower (Helianthus annuus L.) is a widely cultivated oilseed crop with considerable potential globally. Jasmonic acid, a plant growth regulator, plays a crucial role in alleviating the adverse impacts of drought stress on the morphological, biochemical, and physiological characteristics of crops. Experimental detail includes sunflower varieties (Armani Gold, KQS-HSF-1, Parsun, and ESFH-3391), four drought stress levels (0, 25%, 50%, and 75% drought stress), and three levels (0, 40ppm, 80ppm) of jasmonic acid. The 0% drought stress and 0ppm jasmonic acid were considered as control treatments. The experimental design was a completely randomized design with three replicates. Drought stress significantly reduced the growth in all varieties. However, the exogenous application of jasmonic acid at concentrations of 40ppm and 80ppm enhanced growth parameters, shoot and root length (1.93%, 19%), shoot and root fresh weight (18.5%, 25%), chlorophyll content (36%), photosynthetic rate (22%), transpiration rate (40%), WUE (20%), MDA (6.5%), Phenolics (19%), hydrogen peroxide (7%) proline (28%) and glycine betaine (15-30%) under water-stressed conditions, which was closely linked to the increase in stomatal activity stimulated by jasmonic acid. Furthermore, JA 80 ppm was found to be the most appropriate dose to reduce the effect of water stress in all sunflower varieties. It was concluded that the foliar application of JA has the potential to enhance drought tolerance by improving the morphological, biochemical, and physiological of sunflower.

A COMPASS histone H3K4 trimethyltransferase pentamer transactivates drought tolerance and growth/biomass production in Populus trichocarpa.

Histone H3 lysine-4 trimethylation (H3K4me3) activating drought-responsive genes in plants for drought adaptation has long been established, but the underlying regulatory mechanisms are unknown. Here, using yeast two-hybrid, bimolecular fluorescence complementation, biochemical analyses, transient and CRISPR-mediated transgenesis in Populus trichocarpa, we unveiled in this adaptation a regulatory interplay between chromatin regulation and gene transactivation mediated by an epigenetic determinant, a PtrSDG2-1-PtrCOMPASS (complex proteins associated with Set1)-like H3K4me3 complex, PtrSDG2-1-PtrWDR5a-1-PtrRbBP5-1-PtrAsh2-2 (PtrSWRA). Under drought conditions, a transcription factor PtrAREB1-2 interacts with PtrSWRA, forming a PtrSWRA-PtrAREB1-2 pentamer, to recruit PtrSWRA to specific promoter elements of drought-tolerant genes, such as PtrHox2, PtrHox46, and PtrHox52, for depositing H3K4me3 to promote and maintain activated state of such genes for tolerance. CRISPR-edited defects in the pentamer impaired drought tolerance and elevated expression of PtrHox2, PtrHox46, or PtrHox52 improved the tolerance as well as growth in P. trichocarpa. Our findings revealed the identity of the underlying H3K4 trimethyltransferase and its interactive arrangement with the COMPASS for catalysis specificity and efficiency. Furthermore, our study uncovered how the H3K4 trimethyltransferase-COMPASS complex is recruited to the effector genes for elevating H3K4me3 marks for improved drought tolerance and growth/biomass production in plants.

Herbivore exclusion stabilizes alpine grassland biomass production across spatial scales.

There is growing evidence that land-use management practices such as livestock grazing can strongly impact the local diversity, functioning, and stability of grassland communities. However, whether these impacts depend on environmental condition and propagate to larger spatial scales remains unclear. Using an 8-year grassland exclosure experiment conducted at nine sites in the Tibetan Plateau covering a large precipitation gradient, we found that herbivore exclusion increased the temporal stability of alpine grassland biomass production at both the local and larger (site) spatial scales. Higher local community stability was attributed to greater stability of dominant species, whereas higher stability at the larger scale was linked to higher spatial asynchrony of productivity among local communities. Additionally, sites with higher mean annual precipitation had lower dominant species stability and lower grassland stability at both the spatial scales considered. Our study provides novel evidence that livestock grazing can impair grassland stability across spatial scales and climatic gradients.

Constraining long-term model predictions for woody growth using tropical tree rings.

The strength and persistence of the tropical carbon sink hinges on the long-term responses of woody growth to climatic variations and increasing CO2 . However, the sensitivity of tropical woody growth to these environmental changes is poorly understood, leading to large uncertainties in growth predictions. Here, we used tree ring records from a Southeast Asian tropical forest to constrain ED2.2-hydro, a terrestrial biosphere model with explicit vegetation demography. Specifically, we assessed individual-level woody growth responses to historical climate variability and increases in atmospheric CO2 (Ca ). When forced with historical Ca , ED2.2-hydro reproduced the magnitude of increases in intercellular CO2 concentration (a major determinant of photosynthesis) estimated from tree ring carbon isotope records. In contrast, simulated growth trends were considerably larger than those obtained from tree rings, suggesting that woody biomass production efficiency (WBPE = woody biomass production:gross primary productivity) was overestimated by the model. The estimated WBPE decline under increasing Ca based on model-data discrepancy was comparable to or stronger than (depending on tree species and size) the observed WBPE changes from a multi-year mature-forest CO2 fertilization experiment. In addition, we found that ED2.2-hydro generally overestimated climatic sensitivity of woody growth, especially for late-successional plant functional types. The model-data discrepancy in growth sensitivity to climate was likely caused by underestimating WBPE in hot and dry years due to commonly used model assumptions on carbon use efficiency and allocation. To our knowledge, this is the first study to constrain model predictions of individual tree-level growth sensitivity to Ca and climate against tropical tree-ring data. Our results suggest that improving model processes related to WBPE is crucial to obtain better predictions of tropical forest responses to droughts and increasing Ca . More accurate parameterization of WBPE will likely reduce the stimulation of woody growth by Ca rise predicted by biosphere models.

A robust multinutrient kinetic model for enhanced lutein and biomass yields in mixotrophic microalgae cultivation: A step towards successful large-scale productions.

Mixotrophic cultivation holds great promise to significantly enhance the productivities of biomass and valuable metabolites from microalgae. In this study, a new kinetic model is developed, explicitly describing the effect of the most influential environmental factors on both biomass growth and the production of the high-value product lutein. This extensive study of multinutrient kinetics for Tetradesmus obliquus in a mixotrophic regime covers various nutritional conditions. Crucial nutrients governing the model include nitrate, phosphate, and glucose. Using seven state variables and 13 unknown parameters, the model's accuracy was ensured through a well-designed two-factor, four-level experimental setup, providing ample data for reliable calibration and validation. Results accurately predict dynamic concentration profiles for all validation experiments, revealing broad applicability. Optimizing nitrogen availability led to significant increases in biomass (up to fourfold) and lutein production (up to 12-fold), with observed maximum biomass concentration of 6.80 g L-1 and lutein reaching 25.58 mg L-1. Noticeably, the model exhibits a maximum specific growth rate of 4.03 day-1, surpassing reported values for photoautotrophic and heterotrophic conditions, suggesting synergistic effects. Valuable guidance is provided for applying the method to various microalgal species and results are large-scale production-ready. Future work will exploit these results to develop real-time photobioreactor operation strategies.

Enhancement of Biomass Production of Diatom Nitzschia sp. S5 through Optimisation of Growth Medium Composition and Fed-Batch Cultivation.

The growing commercial application of microalgae in different industry sectors, including the production of bioenergy, pharmaceuticals, nutraceuticals, chemicals, feed, and food, demands large quantities of microalgal biomass with specific compositions produced at reasonable prices. Extensive studies have been carried out on the design of new and improvement of current cultivation systems and the optimisation of growth medium composition for high productivity of microalgal biomass. In this study, the concentrations of the main macronutrients, silicon, nitrogen and phosphorus, essential for the growth of diatom Nitzschia sp. S5 were optimised to obtain a high biomass concentration. The effect of main macronutrients on growth kinetics and cell composition was also studied. Silicon had the most significant effect on diatom growth during batch cultivation. The concentration of biomass increased 5.45-fold (0.49 g L-1) at 1 mM silicon concentration in modified growth medium compared to the original Guillard f/2 medium. Optimisation of silicon, nitrogen, and phosphorus quantities and ratios further increased biomass concentration. The molar ratio of Si:N:P = 7:23:1 mol:mol:mol yielded the highest biomass concentration of 0.73 g L-1. Finally, the fed-batch diatom cultivation of diatom using an optimised Guillard f/2 growth medium with four additions of concentrated macronutrient solution resulted in 1.63 g L-1 of microalgal biomass. The proteins were the most abundant macromolecules in microalgal biomass, with a lower content of carbohydrates and lipids under all studied conditions.

Cohesive phycoremediation of pyrene by freshwater microalgae Selenastrum sp. and biodiesel production and its assessment.

In this study, the freshwater microalgae Selenastrum sp. was assessed for the effective degradation of pyrene and simultaneous production of biodiesel from pyrene-tolerant biomass. The growth of algae was determined based on the cell dry weight, cell density, chlorophyll content, and biomass productivity under different pyrene concentrations. Further, lipids from pyrene tolerant culture were converted into biodiesel by acid-catalyzed transesterification, which was characterized for the total fatty acid profile by gas chromatography. Increased pyrene concentration revealed less biomass yield and productivity after 20 days of treatment, indicating potent pyrene biodegradation by Selenastrum sp. Biomass yield was unaffected till the 20 mg/L pyrene. A 95% of pyrene bioremediation was observed at 20 days of culturing. Lipid accumulation of 22.14%, as evident from the estimation of the total lipid content, indicated a marginal increase in corroborating pyrene stress in the culture. Fatty acid methyl esters yield of 63.06% (% per 100 g lipids) was noticed from the pyrene tolerant culture. Moreover, fatty acid profile analysis of biodiesel produced under 10 mg/L and 20 mg/L pyrene condition showed escalated levels of desirable fatty acids in Selenastrum sp., compared to the control. Further, Selenastrum sp. and other freshwater microalgae are catalogued for sustainable development goals attainment by 2030, as per the UNSDG (United Nations Sustainable Development Goals) agenda. Critical applications for the Selenastrum sp. in bioremediation of pyrene, along with biodiesel production, are enumerated for sustainable and renewable energy production and resource management.

A novel Lactiplantibacillus plantarum strain: probiotic properties and optimization of the growth conditions by response surface methodology.

The objective of this study is to explore the probiotic properties and optimal growth conditions of Lactiplantibacillus plantarum BG24. L. plantarum BG24 exhibited a remarkable ability to utilize lactose, and to grow under acidic conditions and in the presence of high levels of bile salts. The strain showed the highest antibacterial activity against L. monocytogenes Scott A (zone of inhibition: 26 mm). L. plantarum BG24 was found to be resistant to 8 of the tested 19 antibiotics using the disc diffusion method.and its multiple antibiotic resistance (MAR) index was calculated as 0.421. The adhesion rate to human intestinal epithelial Caco-2 cells was determined as 37.51%. The enzyme profile of L. plantarum BG24 was investigated using API ZYM test kit and the highest enzymatic activities were found for Leucine arylamidase, ß-glucosidase, Valine arylamidase, ß-galactosidase and N-acetyl-ß-glucosaminidase. L. plantarum BG24 strain showed higher microbial growth under static conditions (6.60 OD600) compared to 100 rpm (5.73 OD600) and 200 rpm (5.02 OD600) shaking speed due to its facultative anaerobic characteristic. However, different inoculation rates and glucose addition did not make a statistically significant difference on biomass formation (p > 0.05). The specific growth rate of L. plantarum BG24 was 0.416 h-1, the doubling time was 1.67 h, and the biomass productivity value was 0.14 gL-1 h-1 in the original MRS broth (pH 5.7) while higher values were found as 0.483 h-1, 1.43 h and 0.17 gL-1 h-1, respectively, in MRS broth (pH 6.5) medium enriched with 5 g/L yeast extract. The stirred tank bioreactor was used to optimise the growth of BG24 strain. The process variables was optimized at 0.05 vvm of aeration rate, 479 rpm of agitation speed, 3% of inoculation rate and 18 h of incubation time. The maximum biomass (g/L) production was obtained as 3.84 g/L at the optimized conditions.

Interactive effects of elevated temperature and drought on plant carbon metabolism: A meta-analysis.

Elevated temperature (Te ) and drought often co-occur and interactively affect plant carbon (C) metabolism and thus the ecosystem C cycling; however, the magnitude of their interaction is unclear, making the projection of global change impacts challenging. Here, we compiled 107 journal articles in which temperature and water availability were jointly manipulated, and we performed a meta-analysis of interactive effects of Te and drought on leaf photosynthesis (Agrowth ) and respiration (Rgrowth ) at growth temperature, nonstructural carbohydrates and biomass of plants, and their dependencies on experimental and biological moderators (e.g., treatment intensity, plant functional type). Our results showed that, overall, there was no significant interaction of Te and drought on Agrowth . Te accelerated Rgrowth under well-watered conditions rather than under drought conditions. The Te × drought interaction on leaf soluble sugar and starch concentrations were neutral and negative, respectively. The effect of Te and drought on plant biomass displayed a negative interaction, with Te deteriorating the drought impacts. Drought induced an increase in root to shoot ratio at ambient temperature but not at Te . The magnitudes of Te and drought negatively modulated the Te × drought interactions on Agrowth . Root biomass of woody plants was more vulnerable to drought than that of herbaceous plants at ambient temperature, but this difference diminished at Te . Perennial herbs exhibited a stronger amplifying effect of Te on plant biomass in response to drought than did annual herbs. Te exacerbated the responses of Agrowth and stomatal conductance to drought for evergreen broadleaf trees rather than for deciduous broadleaf and evergreen coniferous trees. A negative Te × drought interaction on plant biomass was observed on species-level rather than on community-level. Collectively, our findings provide a mechanistic understanding of the interactive effects of Te and drought on plant C metabolism, which would improve the prediction of climate change impacts.

Microalgae Commercialization Using Renewable Lignocellulose Is Economically and Environmentally Viable.

Conventional phototrophic cultivation for microalgae production suffers from low and unstable biomass productivity due to limited and unreliable light transmission outdoors. Alternatively, the use of a renewable lignocellulose-derived carbon source, cellulosic hydrolysate, offers a cost-effective and sustainable pathway to cultivate microalgae heterotrophically with high algal growth rate and terminal density. In this study, we evaluate the feasibility of cellulosic hydrolysate-mediated heterotrophic cultivation (Cel-HC) for microalgae production by performing economic and environmental comparisons with phototrophic cultivation through techno-economic analysis and life cycle assessment. We estimate a minimum selling price (MSP) of 4722 USD/t for producing high-purity microalgae through Cel-HC considering annual biomass productivity of 300 t (dry weight), which is competitive with the conventional phototrophic raceway pond system. Revenues from the lignocellulose-derived co-products, xylose and fulvic acid fertilizer, could further reduce the MSP to 2976 USD/t, highlighting the advantages of simultaneously producing high-value products and biofuels in an integrated biorefinery scheme. Further, Cel-HC exhibits lower environmental impacts, such as cumulative energy demand and greenhouse gas emissions, than phototrophic systems, revealing its potential to reduce the carbon intensity of algae-derived commodities. Our results demonstrate the economic and environmental competitiveness of heterotrophic microalgae production based on renewable bio-feedstock of lignocellulose.

A novel cultivation platform of duckweed (Lemna minor) via application of beeswax superhydrophobic coatings.

Conventional establishment of laboratory cultures of duckweed Lemna minor are prepared in beakers, Erlenmeyer flasks or Schott bottles. These conventional cultivation methods limit the available surface area for growth which then causes layering of fronds that reduces the efficiency of plants in sunlight capturing. Here, acrylic sheets were spray-coated with a superhydrophobic (SHP) beeswax suspension and these coated acrylic sheets were used as a novel cultivation platform for L. minor. L. minor was grown for 7 days in conventional glass jar which acted as the control and were compared to SHP coated acrylic (SHPA) and SHP coated acrylic with aluminium mesh centrally placed (SHPAM) at similar duration and cultivation conditions. Addition of mesh was to entrap the plantlets and fixed the plantlets' position on the growing platform. The effects of cultivation platforms on growth rate and biochemical compositions of L. minor were monitored. The highest biomass growth was obtained from SHPA cultivation where the relative growth rate (RGR) was 0.0909 ± 0.014 day-1 and the RGR was 2.17 times higher than the control. Moreover, L. minor harvested from SHPA displayed the highest values in total protein content, total carbohydrates content and crude lipid percentage. The values were 156.04 ± 12.13 mg/g, 94.75 ± 9.02 mg/g and 7.09 ± 1.14% respectively. However, the control showed the highest total chlorophyll content which was 0.7733 ± 0.042 mg/g FW. Although SHPA obtained a slightly lower chlorophyll content than the control, this growing platform is still promising as it displayed the highest growth rate as well as other biochemical composition. Hence, this study proved that the proposed method that applied superhydrophobic properties in cultivation of L. minor provided a larger surface area for L. minor to grow, which then resulted in a greater biomass production while simultaneously maintaining the quality of the biochemical compositions of duckweeds.

Effect of Chinese medicinal herbal residues compost on tomato and Chinese cabbage plants: Assessment on phytopathogenic effect and nutrients uptake.

Chinese medicinal herbal residues (CMHRs) are known for their antipathogenic properties due to the presence of bioactive compounds. Hence, CMHRs could be used as a potential resource to produce biofertilizer with antipathogenic properties for agricultural applications. In this study, a novel approach was used by utilizing the waste-derived biofertilizer, i.e., CMHRs compost (CMHRC) as a nutrient supplier as well as an organic bioagent against Alternaria solani (A. solani) and Fusarium oxysporum (F. oxysporum) on tomato (Lycopersicon esculentum) and Chinese cabbage (Brassica rapa subsp. Chinensis) plants. The experiments were conducted under greenhouse conditions using locally collected acidic soil wherein 2%, 5% and 10% CMHRC (dry weight) along with 5% food waste compost were used as treatments. In addition, only soil and soil with phytopathogens were used as control treatments. The results suggested that amending the compost into acidic soil significantly increased the pH to a neutral level along with enhanced uptake of nutrients. Among all the treatments, 5% CMHRs compost addition increased the tomato plant biomass production to 4.9 g/pot (dry weight) compared to 2.2 g/pot in control. A similar trend was observed in Chinese cabbage plants and the improved plant biomass production could be attributed to the combined effect of strong nutrient absorption ability by healthy roots and enhanced nutrient supply. At 5% CMHRC application rate, the nitrogen uptake by tomato and Chinese cabbage plants increased by 78% and 62%, respectively, whereas phosphorous uptake increased by 75% and 25%, respectively. The reduction in A. solani by 48% and F. oxysporum by 54% in the post-harvested soil of 5% CMHRC treatment against the control demonstrated the anti-phytopathogenic efficiency of CMHRC compost. Hence, the present study illustrates the beneficiary aspects of utilizing CMHRs to produce biofertilizer with anti-phytopathogenic properties which can be safely used for tomato and Chinese cabbage plant growth.

Trends on Chlamydomonas reinhardtii growth regimes and bioproducts.

The green microalga Chlamydomonas reinhardtii is a model microorganism for several areas of study. Among the different microalgae species, it presents advantageous characteristics, such as genomes completely sequenced and well-established techniques for genetic transformation. Despite that, C. reinhardtii production is still not easily commercially viable, especially due to the low biomass yield. So far there are no reports of scientometric study focusing only on C. reinhardtii biomass production process. Considering the need for culture optimization, a scientometric research was conducted to analyze the papers that investigated the growth regimes effects in C. reinhardtii cultivation. The search resulted in 130 papers indexed on Web of Science and Scopus platforms from 1969 to December 2022. The quantitative analysis indicated that the photoautotrophic regime was the most employed in the papers. However, when comparing the three growth regimes, the mixotrophic one led to the highest production of biomass, lipids, and heterologous protein. The production of bioproducts was considered the main objective of most of the papers and, among them, biomass was the most frequently investigated. The highest biomass production reported among the papers was 40 g L-1 in the heterotrophic growth of a transgenic strain. Other culture conditions were also crucial for C. reinhardtii growth, for instance, temperature and cultivation process.

Advances in Genetic Engineering in Improving Photosynthesis and Microalgal Productivity.

Even though sunlight energy far outweighs the energy required by human activities, its utilization is a key goal in the field of renewable energies. Microalgae have emerged as a promising new and sustainable feedstock for meeting rising food and feed demand. Because traditional methods of microalgal improvement are likely to have reached their limits, genetic engineering is expected to allow for further increases in the photosynthesis and productivity of microalgae. Understanding the mechanisms that control photosynthesis will enable researchers to identify targets for genetic engineering and, in the end, increase biomass yield, offsetting the costs of cultivation systems and downstream biomass processing. This review describes the molecular events that happen during photosynthesis and microalgal productivity through genetic engineering and discusses future strategies and the limitations of genetic engineering in microalgal productivity. We highlight the major achievements in manipulating the fundamental mechanisms of microalgal photosynthesis and biomass production, as well as promising approaches for making significant contributions to upcoming microalgal-based biotechnology.

The Overexpression of Oryza sativa L. CYP85A1 Promotes Growth and Biomass Production in Transgenic Trees.

Brassinosteroids (BRs) are important hormones that play crucial roles in plant growth, reproduction, and responses to abiotic and biotic stresses. CYP85A1 is a castasterone (CS) synthase that catalyzes C-6 oxidation of 6-deoxocastasterone (6-deoxoCS) to CS, after which CS is converted into brassinolide (BL) in a reaction catalyzed by CYP85A2. Here, we report the functional characteristics of rice (Oryza sativa L.) OsCYP85A1. Constitutive expression of OsCYP85A1 driven by the cauliflower mosaic virus 35S promoter increased endogenous BR levels and significantly promoted growth and biomass production in three groups of transgenic Populus tomentosa lines. The plant height and stem diameter of the transgenic poplar plants were increased by 17.6% and 33.6%, respectively, in comparison with control plants. Simultaneously, we showed that expression of OsCYP85A1 enhanced xylem formation in transgenic poplar without affecting cell wall thickness or the composition of cellulose. Our findings suggest that OsCYP85A1 represents a potential target candidate gene for engineering fast-growing trees with improved wood production.

Sustainable treatment of primary and secondary effluent by algal-bacterial flocculent biomass in raceway ponds.

Two 5.5-L raceway open ponds were used to evaluate the removal of organic material and nutrients from wastewater. Algal-bacterial flocs were placed in the ponds to treat primary and secondary effluent. The organic loading rate ranged from 29 to 95 and 9 to 38 g sCOD m-3 d-1 for the reactor fed with primary and secondary effluent, respectively. The hydraulic retention time (HRT) gradually decreased in both reactors from 5.5 to 2.2 d during a period of 21 days, and after that, both reactors operated at an HRT of 1.1 d. A high biomass concentration of around 2.2 g L-1 was sustained using primary and secondary effluent after 130 days. The biomass, developed with both substrates was very active and completely removed organic material and nutrients in less than 12 h. The algal-bacteria biomass had excellent settling properties and could settle in less than 10 min.

Rice straw as microalgal biofilm bio-carrier: Effects of indigenous microorganisms on rice straw and microalgal biomass production.

Microalgal biofilm cultivation is a promising method for efficient microalgae production. However, expensive, difficult-to-obtain and non-durable carriers hinder its up-scaling. This study adopted both sterilized and unsterilized rice straw (RS) as a carrier for the development of microalgal biofilm, with polymethyl methacrylate as control. The biomass production and chemical composition of Chlorella sorokiniana, as well as the microbial community composition during cultivation were examined. The physicochemical properties of RS before and after utilized as carrier were investigated. The biomass productivity of unsterilized RS biofilm exceeded that of suspended culture by 4.85 g m-2·d-1. The indigenous microorganisms, mainly fungus, could effectively fixed microalgae to the bio-carrier and enhance its biomass production. They could also degrade RS into dissolved matters for microalgal utilization, leading to the physicochemical properties change of RS in the direction which favored its energy conversion. This study showed that RS can be used effectively as a microalgal biofilm carrier, thus presenting a new possibility for the recycling of rice straw.

Cellulose-degrading bacteria improve conversion efficiency in the co-digestion of dairy and chicken manure by black soldier fly larvae.

Black soldier fly larvae (BSFL) have potential utility in converting livestock manure into larval biomass as a protein source for livestock feed. However, BSFL have limited ability to convert dairy manure (DM) rich in lignocellulose. Our previous research demonstrated that feeding BSFL with mixtures of 40% dairy manure and 60% chicken manure (DM40) provides a novel strategy for significantly improving their efficiency in converting DM. However, the mechanisms underlying the efficient conversion of DM40 by BSFL are unclear. In this study, we conducted a holistic study on the taxonomic stucture and potential functions of microbiota in the larval gut and manure during the DM and DM40 conversion by BSFL, as well as the effects of BSFL on cellulosic biodegradation and biomass production. Results showed that BSFL can consume cellulose and other nutrients more effectively and harvest more biomass in a shorter conversion cycle in the DM40 system. The larval gut in the DM40 system yielded a higher microbiota complexity. Bacillus and Amphibacillus in the BSFL gut were strongly correlated with the larval cellulose degradation capacity. Furthermore, in vitro screening results for culturable cellulolytic microbes from the larval guts showed that the DM40 system isolated more cellulolytic microbes. A key bacterial strain (DM40L-LB110; Bacillus subtilis) with high cellulase activity from the larval gut of DM40 was validated for potential industrial applications. Therefore, mixing an appropriate proportion of chicken manure into DM increased the abundance of intestinal bacteria (Bacillus and Amphibacillus) producing cellulase and improved the digestion ability (particularly cellulose degradation) of BSFL to cellulose-rich manure through changes in microbial communities composition in intestine. This study reveals the microecological mechanisms underlying the high-efficiency conversion of cellulose-rich manure by BSFL and provide potential applications for the large-scale cellulose-rich wastes conversion by intestinal microbes combined with BSFL.

Miscanthus x giganteus stress tolerance and phytoremediation capacities in highly diesel contaminated soils.

Second generation biofuel crop Miscanthus x giganteus (Mxg) was studied as a candidate for petroleum hydrocarbons (PHs) contaminated soil phytomanagement. The soil was polluted by diesel in wide concentration gradient up to 50 g⋅kg-1 in an ex-situ pot experiment. The contaminated soil/plant interactions were investigated using plant biometric and physiological parameters, soil physico-chemical and microbial community's characteristics. The plant parameters and chlorophyll fluorescence indicators showed an inhibitory effect of diesel contamination; however much lower than expected from previously published results. Moreover, lower PHs concentrations (5 and 10 g⋅kg-1) resulted in positive reinforcement of electron transport as a result of hormesis effect. The soil pH did not change significantly during the vegetation season. The decrease of total organic carbon was significantly lower in planted pots. Soil respiration and dehydrogenases activity increased with the increasing contamination indicating ongoing PHs biodegradation. In addition, microbial biomass estimated by phospholipid fatty acids increased only at higher PHs concentrations. Higher dehydrogenases values were obtained in planted pots compared to unplanted. PHs degradation followed the first-order kinetics and for the middle range of contamination (10-40 g⋅kg-1) significantly lower PHs half-lives were determined in planted than unplanted soil pointing on phytoremediation. Diesel degradation was in range 35-70 % according to pot variant. Results confirmed the potential of Mxg for diesel contaminated soils phytomanagement mainly in PHs concentrations up to 20 g⋅kg-1 where phytoremediation was proved, and biomass yield was reduced only by 29 %.

Effects of operational parameters on the performance of unialgal Oedogonium sp. filamentous algae nutrient scrubbers under controlled environmental conditions.

Filamentous algae nutrient scrubber (FANS) operating parameters can strongly influence algal biomass productivity and nutrient removal. However, few studies to date have investigated the effects of FANS operating parameters such as initial standing crop, harvesting frequency and influent flow rate on biomass productivity and nutrient removal performance, especially for FANS that cultivate a single species of algae. Therefore, the overall aim of this study was to investigate how operating parameters affect the biomass productivity and nutrient removal performance of Oedogonium sp. - a promising species for unialgal FANS. The initial standing crop had a significant effect on biomass productivity, with productivities being highest (8.6 ± 0.5 g DW biomass m-2day-1) when the initial standing crop was 60-70 g DW m-2. However, the daily nutrient removal rate was highest (0.47 ± 0.06 g N m-2 day-1and 1.24 ± 0.13 g P m-2 day-1) at the highest initial standing crop (100-110 DW m-2). Biomass productivity was highest with a three-day growth period, regardless of size of the initial standing crop. Therefore, a four-day harvesting interval was selected as the optimal harvesting regime to promote exponential growth and high biomass production. Influent flow rate had a significant effect on biomass productivity, which was highest (9.3 ± 1.7 g DW m-2 day-1) for the 1 L min-1 flow rate. This flow rate also gave the highest instantaneous nutrient removal rate (0.05 ± 0.02 g N m-3 and 0.14 ± 0.05 g P m-3). Current results suggest that an optimum initial standing crop of 70-80 g DW m-2, harvesting frequency of four days and influent flow rate of 1 L min-1 (16.7 L min-1 m-1 width) were optimal for Oedogonium sp. cultivated on FANS to maximize their biomass production and nutrient removal under controlled laboratory conditions. These results contribute to understanding the impacts of operating parameters on optimizing unialgal Oedogonium sp. FANS biomass production and nutrient removal performance.