Increased Biomass Production Research Articles

Unraveling the Potential of Yarrowia lipolytica to Utilize Waste Motor Oil as a Carbon Source

This study evaluated the potential of Y. lipolytica (CBS 2075 and DSM 8218) to grow in waste motor oil (WMO) and produce valuable compounds, laying the foundation for a sustainable approach to WMO management. Firstly, yeast strains were screened for their growth on WMO (2–10 g·L−1) in microplate cultures. Despite limited growth, the CBS 2075 strain exhibited comparable growth to control conditions (without WMO), while DSM 8218 growth increased 2- and 3-fold at 5 g·L−1 and 10 g·L−1 WMO, respectively. The batch cultures in the bioreactor confirmed the best performance of DSM 8218. A two-stage fed-batch strategy–growth phase in aliphatic hydrocarbons, followed by the addition of WMO (one pulse of 5 g·L−1 or five pulses of 1 g·L−1 WMO), significantly increased biomass production and WMO assimilation by both strains. In experiments with five pulses, CBS 2075 and DSM 8218 strains reached high proteolytic activities (593–628 U·L−1) and accumulated high quantities of intracellular lipids (1.3–1.7 g·L−1). Yeast lipids, mainly composed of oleic and linoleic acids with an unsaturated/saturated fraction > 59%, meet the EU biodiesel standard EN 14214, making them suitable for biodiesel production.

Vascular bundle cell-specific expression of a phosphate transporter improves phosphate use efficiency of transgenic Arabidopsis without detrimental effects

Constitutive overexpression of phosphate (Pi) transporter family 1 often results in the accumulation of toxic levels of Pi, which causes growth retardation in plants. In contrast, we had previously reported that root epidermis-specific overexpression of the phosphate transporter TaPT2 in Arabidopsis leads to improved growth and Pi use efficiency. In the present study, we used promoters AtHKT1;1 and SKOR, which are predominantly expressed in the vascular bundle tissues, to overexpress TaPT2. Transgenic lines exhibited increased shoot growth compared to wild type plants under normal- and low-Pi conditions, along with elevated root Pi and total P content, and higher xylem sap Pi concentration, specifically under low-Pi conditions. This was attributed to moderate Pi accumulation in the xylem parenchyma cells, enhancing the Pi uploading capacity to the xylem. SKOR-TaPT2, however, did not complement pho1 mutant, which was defective in uploading Pi to the xylem. The transcriptional levels of VPT1 and VPT3, which are responsible for transporting excess Pi into a vacuole, were upregulated in SKOR promoter lines under normal-Pi conditions. Our results suggested that root vascular bundle-specific expression of TaPT2 is another promising strategy for increasing biomass production, Pi uptake, and Pi use efficiency while preventing growth retardation in transgenic plants.

Light and temperature culture conditions impact the metabolome of the cyanobacterium of therapeutic interest Planktothricoides raciborskii PMC 877.14

Cyanobacteria are ancient photosynthetic microorganisms with a long evolutionary history that have adapted to inhabit diverse environments, such as thermal waters and muds. To do so, they are known to produce a wide range of bioactive molecules likely involved in adaptative traits such as high light and/or high temperature resistance mechanisms, which makes them particularly interesting for inclusion in thermal treatments and various therapeutic applications.In this study, the impact of higher temperature and light intensity culture conditions on the metabolome of a promising cyanobacterial strain isolated from the muds of the Balaruc-les-Bains thermal station, Planktothricoides raciborskii PMC 877.14, was investigated through liquid chromatography and mass spectrometry analyses. Statistical analyses of the biological data and molecular network construction allowed for the exploration of potential metabolite induction under different culture conditions, in order to drive the production of specific metabolites aimed at coping with cellular stress. A global shift on intracellular metabolic composition was observed over time with increased biomass production. Higher light intensity was found to stimulate both growth and production of antioxidant and/or photoprotective molecules (such as ergothioneine, mycosporine-like amino acids or carotenoids) while an increase in temperature influenced the higher production of phycobilins (such as phycoerythrin and phycocyanin).These results highlight the importance of culture/environmental conditions in driving intracellular metabolite differentiation and open up new perspectives in selecting of the optimal parameters for the growth and production of bioactive molecules for therapeutic applications in the cyanobacterium P. raciborskii PMC 877.14.

Predicting potential biomass production by geospatial modelling: The case study of citrus in a Mediterranean area

Residual biomass from agricultural production and processing, such as citrus pulp and olive pomace, is an important resource for energy production. In particular, this is the case in regions where transformation industries are concentrated.Current biomass estimates often focus on actual production data, that may not fully capture the biomass potential across all suitable cultivation areas. To bridge this gap, the study predicts the overall potential biomass available for energy production, taking into account the total area suitable for citrus cultivation.The research is focused on the study of citrus species in the province of Syracuse, Sicily, Italy. The methodology combines Geographic Information System (GIS) tools, for data interpolation and map overlays, with Software for Assisted Habitat Modelling (SAHM) for local level simulations.The results of the different models showed accurate and spatially coherent predictions, with AUC values ranging from 0.85 to 0.90, and highest potentialities in the northern and eastern regions of the study area. The results highlighted potential citrus cultivation on 47,706 ha and estimated 184,340 t of biomass, 16,461,520.82 Nm3 of biogas, and 8110 t of digestate. The results of the study identified potential areas for both increasing biomass production and optimising the distribution of digestate, thus demonstrating the utility of these thematic maps as a decision support tool for land management. The simulations and the methodology applied in this study indicated potential economic and environmental benefits to be gained from sustainable by-product management. This approach facilitates the optimisation of decision-making processes for land planning, thereby contributing to the broader objective of improving resource efficiency and sustainability in the agricultural production and processing sectors.

Microclimate and the spatio-temporal dynamics of natural production of two ectomycorrhizal fungi from the Guineo-Sudanian ecozone in Benin

The study aims to determine the relation between the micro-climate and the natural production of Amanita subviscosa, and Lactifluus gymnocarpoides, in the Guinea-Sudanian ecozone. Nine permanent plots of 50 ×50 m were installed in three different vegetations of the “Ouémé Supérieur” forest reserve in central Benin. The mycological surveys were carried out during three (3) mycological seasons, each from June to October at a frequency of two visits per week and per plot. The number of fruiting bodies and the fresh biomass were recorded. Microclimatic parameters (soil water content, air temperature, soil temperature, relative humidity and precipitation) were measured using a rain gauge and a HOBO micro station data logger installed at the middle of each plot. We tested several Generalized Linear Mixed Effects Models (GLMM) using the lme4 package to obtain the effect of recorded microclimate factor on the number of fruit bodies of each species and the Linear Mixed Effects Model (LMM) using the package nlme for fresh biomass. The study showed that soil water content is the main driver of fungal fruiting phenology and increased biomass production. The fruiting of A. subviscosa is positively affected by air temperature and soil water content (p = 0.0004) but negatively affected by relative air humidity. The fructification of L. gymnocarpoides is only positively affected by the air temperature and negatively affected by relative air humidity and soil water content. Soil water content significantly affects the fresh biomass of A. subviscosa (p≈0) while the fresh biomass of L. gymnocarpoides is significantly affected by soil water content and relative air humidity (p≈0). All species for their natural production have specific response at microclimate parameters variation.

Optimal fertilization of Marandu grass with gelatin industry sludge

This study determined optimal fertilization levels for Marandu grass (Urochloa brizantha cv. Marandu) as a forage using sludge from the gelatin industry. The experiment was performed in a greenhouse with five treatments: three rates of gelatin sludge application (0, 200, and 300 m3 ha-1), an organo-mineral (100 m3 ha-1 + mineral: 60 mg dm-3 N), and pure mineral fertilizer (100 mg dm-3 N) with six replicates. Plant and stem height, number of tillers, leaves, leaves/tiller, chlorophyll index, dry mass (leaves, roots, and residue), crude protein, neutral and acid detergent fiber, macronutrient, and micronutrient concentrations were measured. Plant and stem height, number of tillers, leaves, and biomass production increased linearly as gelatin sludge dosage increased. There was a linear increase in crude protein with reduction in neutral detergent fiber and acid detergent fiber with increasing gelatin sludge fertilization. Gelatin sludge dosage did not affect the contents of P, Mg, S, Cu, and Fe. Only Mn had a positive linear response to gelatin sludge with reduction at the highest rate. The 300 m3 ha-1 dosage of gelatin sludge increased biomass production and chlorophyll index. In contrast, the organo-mineral fertilizer promoted higher crude protein and lower neutral detergent fiber concentrations in grass. The gelatin sludge dosage of 300 m3 ha-1 improved the nutritive value of Marandu grass compared to mineral fertilizer. Gelatin sludge is a promising pasture amendment for growing Marandu grass as it recycles industrial animal waste for a more integrated livestock-cropping system.

Distinguishing High Daytime From Nighttime Temperature Effects During Early Vegetative Growth in Cotton

ABSTRACTHigh‐temperature limits early season vegetative growth of cotton, and the physiological response of cotton (Gossypium hirsutum L.) to high daytime or nighttime temperature needs to be explored. The objectives of the current study were to determine (1) plant growth response, (2) physiological contributors to variation in biomass production and (3) mechanisms driving variation in net photosynthetic rate (AN) in response to different combinations of high daytime and nighttime temperatures. Beginning at planting, cotton was exposed to four different growth temperature regimes: (1) optimum (30/20°C day/night), (2) high nighttime (30/30°C), (3) high daytime (40/20°C) and combined high daytime and nighttime (40/30°C) for 4 weeks. Relative to the 30/20°C treatment, plant growth was positively affected by high nighttime temperature and negatively affected by high daytime temperature and combined high day and night temperature. Increased leaf area mainly contributed to increased biomass production in high nighttime temperature; higher nighttime respiration (RN) drove reductions in biomass in combined high daytime and nighttime temperature; and decreased leaf area and AN and increased RN drove reductions in biomass under high daytime temperature alone. AN was not impacted by high nighttime temperature, while decreased under high daytime temperature and increased with combined high daytime and nighttime temperature. Adjustments in leaf traits contributed to increases in AN in combined high daytime and nighttime temperature, and increased photorespiration and respiration contributed to reductions in AN under high daytime temperature. Overall, early season vegetative growth of cotton exhibited differential responses to high daytime and nighttime temperatures.

Engineering the Rhizosphere Microbiome with Plant Growth Promoting Bacteria for Modulation of the Plant Metabolome.

Plant-growth-promoting bacteria (PGPB) have beneficial effects on plants. They can promote growth and enhance plant defense against abiotic stress and disease, and these effects are associated with changes in the plant metabolite profile. The research problem addressed in this study was the impact of inoculation with PGPB on the metabolite profile of Salicornia europaea L. across controlled and field conditions. Salicornia europaea seeds, inoculated with Brevibacterium casei EB3 and Pseudomonas oryzihabitans RL18, were grown in controlled laboratory experiments and in a natural field setting. The metabolite composition of the aboveground tissues was analyzed using GC-MS and UHPLC-MS. PGPB inoculation promoted a reconfiguration in plant metabolism in both environments. Under controlled laboratory conditions, inoculation contributed to increased biomass production and the reinforcement of immune responses by significantly increasing the levels of unsaturated fatty acids, sugars, citric acid, acetic acid, chlorogenic acids, and quercetin. In field conditions, the inoculated plants exhibited a distinct phytochemical profile, with increased glucose, fructose, and phenolic compounds, especially hydroxybenzoic acid, quercetin, and apigenin, alongside decreased unsaturated fatty acids, suggesting higher stress levels. The metabolic response shifted from growth enhancement to stress resistance in the latter context. As a common pattern to both laboratory and field conditions, biopriming induced metabolic reprogramming towards the expression of apigenin, quercetin, formononetin, caffeic acid, and caffeoylquinic acid, metabolites that enhance the plant's tolerance to abiotic and biotic stress. This study unveils the intricate metabolic adaptations of Salicornia europaea under controlled and field conditions, highlighting PGPB's potential to redesign the metabolite profile of the plant. Elevated-stress-related metabolites may fortify plant defense mechanisms, laying the groundwork for stress-resistant crop development through PGPB-based inoculants, especially in saline agriculture.

Effect of Seed Rate on Forage Yield, and Nutritional Value of Sudan Grass and Vetch Mixtures in Ethiopia: A Review

The livestock feed resources in Ethiopia are classified as natural pasture, crop residues, improved pasture and forage, agro-industrial by-products, and also hay production of which the first two feed resources are the major feed contributors for the livestock production in Ethiopia but they are lacking in protein and minerals. Natural pastures contribute about 80-85 of animal feed in Ethiopia, including naturally occurring grasses, legumes, shrubs, hurbs, and tree foliages. Crop residue is one of the feed resources used for animal production in Ethiopia and is available in those areas in which livestock and crop production are practiced. Around 30 million tonnes of DM of agricultural crop residues are produced annually on the national scale, of which 70% are used as animal feed. The major agro-industrial by products commonly used in Ethiopia are obtained from different agro-industries. The nutritional values of agro-industrial by products are excellent but their productivity is small, limited, and limited to few farms in urban and peri-urban areas and they contribute much less to livestock feed. Furthermore, traditional livestock feed supply mainly depends upon natural pasture and crop residues, which have low crude protein and other chemical composition. However, there is tremendous potential to alleviate feed shortages using improved forage production. To fulfill this gap, producing a stable improved forage in the livestock sector is mandatory. For that reason, the legume and grass intercropping system are important to increase biomass production and forage yield. Hence, Sudan grass (Aden gode) known with its plant height than other cultivars and vetch (<i>Vicia dasycarpa</i>) have greater plant height and creeping growth habit that enable compatible to larger grass species and they are selectable forages to enhance the forage yield and quality under similar times.

Synergistic effects of heterotrophic and phototrophic metabolism for Haematococcus lacustris grown under mixotrophic conditions

AbstractMixotrophic cultivation of Haematococcus lacustris is one of the most promising strategies to produce natural astaxanthin. During mixotrophic growth, microalgae assimilate and metabolize organic carbon in addition to photosynthetic growth, resulting in increased biomass productivity. Several studies have evaluated the effect of different organic carbon sources on mixotrophic growth in various microalgae species. However, knowledge of detailed growth kinetics as a function of substrate concentration and light intensity is lacking. In this study, the growth kinetics of H. lacustris using four different carbon sources and the effect of light under mixotrophic and photoautotrophic conditions are described. Mixotrophic cultivation showed significant differences in respect to applied substrate and achieved maximum specific growth rates of 0.91 ± 0.13, 0.19 ± 0.05, 0.36 ± 0.05, and 0.23 ± 0.05 day−1, for acetate, methanol, glucose, and glycerol, respectively. Optimal growth at mixotrophic conditions using acetate was 1.8 times higher than the sum of hetero- and photoautotrophic growth. Furthermore, the optimum light intensity was 1.3 times higher for mixotrophic than for autotrophic growth. Thus, mixotrophy increases light intensity tolerance. These results indicate a strong interconnection between carbon metabolism and photosynthetic activity and lay the foundation for more detailed mathematical models describing the mixotrophic growth of H. lacustris. Graphical Abstract

Arbuscular mycorrhizal fungi increased biomass, nutritional value, and cochineal resistance of Opuntia ficus-indica plants

BackgroundOpuntia ficus-indica (L.) Miller is dominantly growing on degraded soils in arid and semi-arid areas. The plants might establish a strong association with arbuscular mycorrhizal fungi (AMF) to adapt to nutrient, drought, and herbivore insect stress. The objective of this study was to investigate the effects of AMF inoculations and variable soil water levels (SWA) on the biomass, nutrient concentration, nutritional composition, and nutrient digestibility of the spiny and spineless O. ficus-indica by inducing resistance to cochineal stress. One mother Opuntia ficus-indica cladode was planted in a single pot in each field with 24 kg mixed soil. AMF inoculums were cultured in sorghum plants in a greenhouse and were inoculated in the planted cladodes. The planted cladodes were arranged using a completely randomized design (CRD) with three factors: AMF (present and absent); O. ficus-indica type (spiny and spineless) and four water treatments with 0–25% of plant available soil water (SWA), 25–50% of SWA, 50–75% of SWA, and 75–100% of SWA.ResultsDrought stress reduced the below and above-ground biomass, cladode nutrient content, nutritional composition, and in vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD). AMF colonization significantly increased biomass production with significant changes in the macro and micro-nutrient concentrations of O. ficus-indica. AMF inoculation significantly increased the IVDMD and IVOMD of both O. ficus-indica types by improving the biomass, organic matter (OM), crude protein (CP), and reduced fiber and ash contents. AMF-inoculated cladodes improved the nutrient concentrations of the cladodes. AMF caused an increase in biomass production, increased tolerance to cochineal stress, and improved nutrient concentration, nutritional composition, and nutrient digestibility performance of O. ficus-indica plants.ConclusionsAMF improved the performance of the O. ficus-indica plant to resist drought and cochineal stress and increased the biomass, nutrient concentration, nutritional composition, and nutrient digestibility. The potential of O. ficus-indica to adapt to cochineal stress is controlled by the macro and micro-nutrient concentration brought by the AMF association.

Phosphate Fertilization Without Pasture Burning Increase Biomass Productivity and Reduce Carbon Loss

Objective: In this work we evaluate the phosphorus fertilization without burning on the biomass productivity and the reduction of carbon loss from the pasture of Brachiaria brizantha in the Brazilian Amazon. Theoretical Framework: Brachiaria brizantha is the main cultivated pasture species in Brazil. The overgrazing and no nutrient replenishment in addition to the periodical burnings are the trigger factors of a gradual degradation since the 70’s in the Amazon. That fact suggests the need for research solutions to eliminate the use of this practice for pasture management. Method: A field experiment was carried out from September to November 2015 in a completely randomized blocks design. The treatments consisted of unburned pasture treated with 0, 25, 100 and 200 kg ha-1 of phosphorus compared to the pasture burning, with 4 blocks and 20 experimental plots. The experimental plots treated with phosphorus received agronomic doses of potassium and nitrogen applied on the soil surface. After applying the treatments, including the burning, the pasture was desiccated in order to homogenize the plant emergence and growth after the period without rain from July to September. Results and Discussion: The soil fertility attributes, components of biomass productivity, partial carbon stocks and the partial carbon retained in the pasture (not lost as carbon dioxide) were quantified at 56 days after the beggining of the experimental period. In comparison to the pasture burning, the treatments alter the soil phosphorus availability and, as a result, increase the partial biomass productivity and its carbon content, reducing the loss of carbon dioxide to the atmosphere. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of pasture management without fire using. These implications could encompass on how to apply and how much of an alternative phosphate must be applied to the soil in order to supply phosphorus for B. brizantha instead of using fire as a strategy of pasture management. Originality/Value: This study contributes to the literature by highlighting the superiority of phosphorus application from alternative source allied to N and K fertilization compared to the pasture burning practice in the Southwestern Amazon. This innovative approach can be used as a base for new researches and applied in the level of cattle farmers.

Effects of Winery Wastewater to Soils on Mineral Properties and Soil Carbon

Winery wastewater (WW) is a high-volume biowaste and, in the context of Marlborough and New Zealand wineries, there is a growing recognition of the need to improve current WW disposal systems to mitigate negative environmental impacts. The application of WW to land is a low-cost method of disposal, that could significantly reduce the environmental risk associated with WW directly entering surface and groundwater bodies. This study analysed elemental concentrations in WW and soils from three Marlborough vineyards across their annual vintage to determine the loading rates of nutrients into WW and the subsequent accumulation effects of WW irrigation on receiving soils. The findings showed loading rates of approximately 1.8 t ha−1 yr−1 of sodium within WW and a significant increase in soil sodium concentration and pH, attributed to sodium-based cleaning products. A loading rate of approximately 4 t ha−1 yr−1 of total organic carbon was also identified within WW, however, significant losses in soil carbon, nitrogen, magnesium and calcium concentrations were identified. Focusing efforts to retain key nutrients from WW within soils could provide benefits to New Zealand’s wine industry, facilitating increased biomass production in irrigation plots, thereby increasing biodiversity and potentially generating incentives for vineyard owners to contribute to increasing biomass carbon stocks and offset agricultural greenhouse gas emissions.

Antioxidative Response of Duckweed (Lemna minor L.) to Rhizosphere-Associated Pseudomonas Strains and Exogenous Indole-3-Acetic Acid

Aquatic plants, just like terrestrial plants, are exposed to oxidative stress. However, their responses are still under-researched. In this study, we examined the physiological and antioxidative responses of an aquatic plant, duckweed (Lemna minor L.), to four indole-3-acetic acid (IAA)-degrading and -producing Pseudomonas bacteria (Pseudomonas oryzihabitans D1-104/3, P. putida A3-104/5, P. gessardii C31-106/3 and P. yamanorum C44-104/1) and/or a supraphysiological level of IAA (10 mg L−1). Growth characteristics, total photosynthetic pigment content, histochemical localization of reactive oxygen species and antioxidant enzyme activity (SOD, CAT and POX) were evaluated at two time points, after 3 and 7 days of co-cultivation. Superoxide anion and hydrogen peroxide were produced and accumulated mainly in the roots, daughter fronds and veins of duckweeds. Duckweeds’ responses depended on the strain of Pseudomonas, time and exogenous IAA. Co-cultivation of duckweed with bacteria has positive or neutral effects. Exogenous application of IAA had a negative or neutral effect on enzyme activity and other parameters. Co-cultivation with P. gessardii C31-106/3 showed plant-growth-promoting effects on duckweed: increased biomass production, modulation of duckweeds’ antioxidant enzymatic activity and reduction in hydrogen peroxide content. This study widens our knowledge of aquatic plants and their response to oxidative stress, supports the hypothesis that plant growth-promoting bacteria (PGPB) induce tolerable levels of oxidative stress in plants and introduces a new PGPB strain, P. gessardii C31-106/3.

Unveiling the aluminum tolerance by Tithonia diversifolia grown in acid soil: Insights from morphological, anatomical, and nutritional analysis

AbstractAcidic soils cover two‐thirds of Brazil's land, significantly reducing pasture productivity and resilience. Tithonia diversifolia has emerged as a promising forage alternative for such soils. The objective of this study was to assess the effect of different soil acidity levels, determined by base‐cation saturation (BCS) levels, on the anatomical, and morphological analyses of the roots, the nutritional status of the plants, as well as the root and shoot biomass production. A 107‐days greenhouse experiment was carried out, employing a randomized block design with a 2 × 4 factorial arrangement. The factors included two propagation methods (seeds and stem cuttings) and four BCS levels (19%, 39%, 52%, and 63%). There was no observed interaction between propagation methods and BCS levels regarding root and shoot biomass production. This indicates that T. diversifolia's tolerance to acidic soils is not affected by the propagation method. However, stem‐propagated plants exhibited significantly greater root (31% increase) and shoot (26% increase) biomass production compared to seed‐propagated plants. Regardless of the propagation method, T. diversifolia plants grown in soil with a 19% BCS level showed a substantial reduction in root (45% decrease) and shoot (31% decrease) biomass compared to the 63% BCS level treatment. The root anatomy and morphology of T. diversifolia are affected when cultivated in acidic soils with a 19% BCS level. Nevertheless, the Periodic Acid Schiff (PAS) test detected some mucilage in T. diversifolia roots, suggesting a potential defense mechanism for Al3+. The shoot biomass of T. diversifolia plants cultivated in soil with a 19% BCS level exhibited greater nutritional values compared to the 63% BCS level. In conclusion, propagation methods have a limited impact on the tolerance of T. diversifolia to acidic soils. Despite the negative effects on root and shoot biomass production, T. diversifolia effectively maintains nutrient uptake even under acidic soil conditions with Al3+ availability of 5 mmolc dm−3.

Evaluation of the nitrogen uptake efficacy of daikon radish under greenhouse conditions on sandy soils

AbstractCover crops can be a great addition to agricultural systems to improve soil health and nutrient cycling. One of the many qualities that cover crops possess is recovering residual nutrients. This study was established to estimate daikon radish (Raphanus sativus var. Longipinnatus) nitrogen (N) uptake, partitioning, and accumulation in a short time in Florida conditions. In greenhouse conditions, two Florida sandy soils were planted with daikon radish with three N rates (0, 50, and 101 kg N ha−1 as urea) following a randomized complete block with four replications. The treatments were organized in a two‐by‐three full factorial arrangement with the three N fertilizer rates. Biomass accumulation, N uptake, and partitioning into shoots and roots were estimated, and residual soil N was calculated. Increasing the amount of N applied to daikon radish plants did not increase biomass production or N accumulation in the shoots and roots of the plants. Daikon radish plants grown without N fertilization were able to produce a similar amount of biomass as those with N applications in their early growth stage. This suggests that daikon radish has the potential to adapt to the sandy soils of Florida and could efficiently utilize the residual soil N. This study shows the potential use of daikon radish as a cover crop in the row middles of citrus groves. The findings suggest that daikon radish plants could thrive in these unfertilized areas and offer promising benefits to the citrus orchards in terms of providing ground cover and additional advantages.

Weeds and Their Response to Changing Climate: A Review

Climate change is one of the most important parameters to cause alteration in weed composition, population growth, life processes, physiological development, and infestation pressure. A few of the weed species may become inactive, while the rest may become aggressive invaders. Weeds possess unique biological characteristics and ecological range that enable them to tolerate and successfully intrude in any ecosystem with varied environmental conditions. Rising carbon dioxide, will benefit C3 crops to expand their photosynthetic capacity, thus leading to increased biomass production and productivity, on the other hand increased temperatures will benefit the C4 crops. These differences in response of C3 and C4 crops to changing climate will influence crop-weed interaction, most likely at the expense of crop. Moisture is another important environmental factor which plays a major role in weed seed germination, thus the survival. Temperature and relative humidity influence the course of absorption, translocation, and metabolism of herbicides in plants, any change in their range leads to decreased herbicide efficacy and thus the weed control. Studies focussed on the performance of weeds under elevated environmental factors help to make strategic decisions on their management before having their impact on change in weed biological aspects, and foresee the future with elevated temperature and carbon dioxide conditions. Weeds such as Parthenium hysterophorus, Sphagneticola trilobata, Prosopis juliflora and Eichhornia crassipes, have been identified as potential future threats. Consequently, exploring the bioprospecting potential of these weeds is seen as an inevitable necessity.

Enhancing high-density microalgae cultivation via exogenous supplementation of biostimulant derived from onion peel waste for sustainable biodiesel production

Microalgae demonstrate significant potential as a source of liquid-based biofuels. However, increasing biomass productivity in existing cultivation systems is a critical prerequisite for their successful integration into large-scale operations. Thus, the current work aimed to accelerate the growth of C. vulgaris via exogenous supplementation of biostimulant derived from onion peel waste. Under the optimal growth conditions, which entailed a biostimulant dosage of 37.5% v/v, a pH of 3, an air flow rate of 0.4 L/min, and a 2% v/v inoculum harvested during the mid-log phase, yielded a maximum biomass concentration of 1.865 g/L. Under the arbitrarily optimized parameters, a comparable growth pattern was evident in the upscaled cultivation of C. vulgaris, underscoring the potential commercial viability of the biostimulant. The biostimulant, characterized through gas chromatography-mass spectrometry (GC-MS) analysis, revealed a composition rich in polyphenolic and organo-sulphur compounds, notably including allyl trisulfide (28.13%), methyl allyl trisulfide (23.04%), and allyl disulfide (20.78%), showcasing potent antioxidant properties. Additionally, microalgae treated with the biostimulant consistently retained their lipid content at 18.44% without any significant reduction. Furthermore, a significant rise in saturated fatty acid (SFA) content was observed, with C16:0 and C18:1 dominating both bench-scale (44.08% and 14.01%) and upscaled (51.12% and 13.07%) microalgae cultures, in contrast to the control group where C18:2 was prevalent. Consequently, SFA contents reached 54.35% and 65.43% in bench-scale and upscaled samples respectively, compared to 33.73% in the control culture. These compositional characteristics align well with the requirements for producing high-quality crude biodiesel.

Evaluation of Microalgae Chlorella vulgaris and Tetradesmus bernardii for Cultivation and Nutrient Removal in Palm Oil Mill Effluent

The palm oil industry is one of the key players in contributing to Malaysia’s economy. Palm oil mill effluent (POME), a significant by-product of the oil extraction process, requires mandatory remediation to ensure proper treatment and disposal. Bioremediation using microalgae is a cost-effective and sustainable approach. This study aims to utilise pure and mixed microalgal species, Chlorella vulgaris and Tetradesmus bernardii, in phycoremediation and biomass production in different concentrations of POME (20%, 40%, 60%, and 80%). Cultivation of microalgae was carried out in 200 mL medium with pH 7–7.8, room temperature of 25±1°C for 21 days and continuous light illumination at 2000 lux. The highest biomass productivity was observed in 20% POME for mixed microalgae (mean = 0.1733 mg.mL-1 ± 0.0057), followed by C. vulgaris (0.1633 mg.mL-1 ± 0.0057) and T. bernardii (0.1603 mg.mL-1 ± 0.0020). Similarly, the highest nutrient removal was observed in 20% POME for mixed microalgae (COD:66.9801%, TN:86.9565%, TP:86.9655%), followed by C. vulgaris and T. bernardii. The results showed positive effects on growth, increased biomass production, and nutrient removal, with 20% POME being the optimal concentration for microalgae. Valuable by-products, such as high-quality pigments and biomass, are also generated by applying microalgae for remediation. Mixed microalgae are superior in the remediation of POME compared to single-culture algae. Treating wastewater through microalgal bioremediation is highly efficient in nutrient removal. This research has contributed towards the use of mixed microalgae to achieve effective nutrient removal and biomass for future industrial applications.

Exploring microalgal nutrient-light synergy to enhance CO2 utilization and lipid productivity in sustainable long-term water recycling cultivation

In this work the effects of nutrient availability and light conditions on CO2 utilization and lipid production in Micractinium pusillum KMC8 is reported. The study investigated the ideal nitrogen concentrations for growth and nitrogen utilization in a 15% CO2 environment. Logistic and Gompertz models were employed to analyze the kinetics of KMC8 cell growth. Compared to 17.6 mmol L−1 control nitrogen, which generated 1.6 g L−1 growth, doubling and quadrupling nitrogen concentrations boosted biomass growth by 12.5% and 28.78%. At 8.6 mmol L−1 nitrogen, the growth decreased but lipid productivity increased to 18.62 mg L−1 day−1. At 70.6 mmol L−1 nitrogen, elevated nitrogen levels maintained an alkaline pH above 7 and enhanced CO2 mitigation, achieving 2.27% CO2 utilization efficiency. Nitrogen shows a positive correlation with higher rates of carbon and nitrogen fixation. The investigation extends to find out the influence of phosphorus and light conditions on microalgae. Increasing light intensity incrementally from 150 to 1200 μmol m−2 s−1 with more phosphorus increased biomass productivity by 85% (255 mg L-1 day−1) and lipid productivity by 2.5-fold (84.76 mg L-1 day−1), with 3.3% CO2 utilization efficiency compared to directly using 1200 μmol m−2 s−1. This study suggests a water recycling-fed batch cycle with gradual light feeding, which results in high CO2 fixation (1.1 g L−1 day−1), 7% CO2 utilization, and significant biomass and lipid productivity (577.23 and 150 mg L−1 day−1). This approach promotes lipid synthesis, maintains carbon fixation, and minimizes biomass loss, thus supporting sustainable bioenergy development in a circular bio-economy framework.