Search Results (362)

Agro-industrial residues from livestock and sugarcane production—particularly abundant in regions such as Veracruz, Mexico, where both agro-industries co-occur in high density—constitute underutilized carbon and nitrogen streams with high potential for biotransformation within circular bioeconomy frameworks. This study aimed to evaluate whether inoculation with Lactobacillus delbrueckii subsp. bulgaricus SP96 at increasing levels (5, 10, and 15% v/v) achieves simultaneous stabilization, carbohydrate-to-lactic-acid conversion, and nutritional enrichment of a thermally pretreated bovine manure (BM)–agro-sugarcane waste (ASCW) mixture, and to describe the underlying growth kinetics using the Gompertz model. Thermal pretreatment reduced Salmonella spp. and fecal coliforms to levels compliant with NOM-004-SEMARNAT-2002 Class B biosolid standards, yielding a substrate with suitable fermentability (14.56 gL⁻¹ carbohydrates, 0.44% total nitrogen, pH 6.52, and 90.43% volatile solids). Fermentation at 37 °C and 120 rpm for 72 h followed Gompertz kinetics (R² = 0.92–0.97). The 15% inoculum achieved the highest conversion efficiency and product yield (lactic acid and carbohydrate consumption), whereas the 10% inoculum represented the most balanced operating condition (best kinetic fit, R² = 0.97). However, differences in lactic acid concentration among treatments were not statistically significant (p > 0.05). The resulting biomass showed high organic matter (93.45%), increased crude protein (8.5%), a C/N ratio of 39.9, and enrichment in P₂O₅, MgO, Na₂O, and B. These findings validate a low-cost, scalable platform for simultaneous waste stabilization and generation of value-added, protein-enriched biomass with potential application as a feed supplement and soil amendment, pending further safety and functional characterization, from agro-livestock residues. Full article

Water deficit is one of the most critical factors for determining the growth and yield of sugarcane. Understanding the physiological and molecular mechanisms of sugarcane responses is essential for developing resilient cultivars. In this study, three sugarcane cultivars, NX04 (sensitive), BL (moderate), and NXI-4T (tolerant), were grown in a greenhouse for 2 months and then subjected to drought stress for 8 days after planting. Morphological variation showed that the tolerant sugarcane cultivar exhibits a longer root system and delays leaf chlorosis and rolling. Malondialdehyde (MDA) content was increased in the sensitive and moderate cultivars, although it slightly increased in the tolerant cultivars at 8 days after drought stress. The increase was accompanied by increases in proline content and in gene expression of the catalase (Cat) and ascorbate peroxidase (Apx) across all cultivars, which protect cells from oxidative damage. Interestingly, the expression of the photosynthetic Pepc (phosphoenolpyruvate carboxylase) and Sps (sucrose-phosphate synthase) genes was significantly decreased, whereas SPS activity increased under drought stress. This implies that the SPS protein may be regulated through post-translational modification. The expression of transcription factors (TFs) of NAC, rather than DREB, was significantly upregulated in the tolerant cultivar under 8 days of drought stress, in line with the delay of chlorosis. Full article

Manganese toxicity severely restricts the growth and yield of sugarcane in acidic soil. However, the molecular mechanism of the specific tolerance of different genotypes to manganese remains unclear. This study aims to identify and functionally characterize the ZIP manganese transporter genes in sugarcane, and to elucidate the differences in manganese regulatory mechanisms between the sensitive type GT32 (Saccharum hybrid cultivar) and the tolerant type ZZ1 (Saccharum hybrid cultivar). Through phylogenetic analysis, conserved motifs and cis-acting element analysis, as well as Ka/Ks analysis, a total of 24 ZIP genes were identified in three different sugarcane genotypes. Combined with hydroponic manganese stress treatments, quantitative reverse transcription PCR (qRT-PCR), ion concentration measurements and chlorophyll analysis, physiological and transcriptional differences between ZZ1 and GT32 were compared. Yeast complementation experiments verified the manganese transport ability of ScIRT1 and ScZIP3. Under manganese stress conditions, the results showed that the chlorophyll content of ZZ1 was 41.14% higher than that of GT32, and the manganese accumulation in roots and stems was lower. Significant differences were also observed in the transcriptional patterns of ZIP genes in roots and stems. The qRT-PCR results indicated tissue-specific differences: the transcription level of ScZIP7 in the roots of GT32 was 10 times higher, while ZZ1 maintained the high transcription level of ScZIP3 under manganese stress. The genotype-dependent expression patterns of ScIRT1, ScZIP3, ScZIP6, and ScZIP7 may contribute to the regulation of manganese uptake and intracellular distribution, thereby contributing to the enhanced manganese tolerance observed in ZZ1. These findings provide valuable insights into the molecular basis of manganese tolerance and highlight potential candidate genes for the genetic improvement in manganese-tolerant sugarcane varieties. Full article

This research evaluated the biocontrol potential of the bacterial flora from cured sugarcane bagasse (SCB) against Fusarium oxysporum f. sp. lycopersici (Fol), the causal agent of tomato Fusarium wilt. Screenings of twenty SCB-derived isolates revealed consistent antagonistic activity, inhibiting mycelial growth from 32.08% to 55.00%. The most effective isolate, 100MTN1, was identified via 16S rRNA sequencing (GenBank: PX506225) as Bacillus atrophaeus. Interaction between B. atrophaeus 100MTN1 and Fol FOLViF has revealed a distinct profile of bioactive metabolites produced specifically during co-cultivation. Transcriptomic profiling of Fol FOLViF exposure to 100MTN1 identified 189 differentially expressed genes, with downregulation of genes involved in DNA replication, translation, and membrane transport, and upregulation of those linked to secondary metabolism and oxidative stress. KEGG pathway mapping further supported the possible causes of disruptions within the pathogen. Molecular docking suggested that the B. atrophaeus 100MTN1 derived metabolite, 6-Hydroxy-3′-methoxyflavone and exhibits binding affinity for key Fol proteins that compares favorably with the commercial fungicides. Greenhouse trials using tomato cv. Kalyan confirmed that treatment with strain 100MTN1 was associated with reduced disease severity and enhanced plant growth. These findings suggest that B. atrophaeus 100MTN1 suppresses Fol FOLViF through a combination of metabolite-driven inhibition and transcriptional interference, signifying its potential as a biological control agent for managing Fusarium wilt. Full article

Reliance on mineral fertilization in papaya cultivation raises sustainability concerns and drives demand for validated organic alternatives. This study tested whether integrating humic substances (HS) and sugarcane filter cake (FC) would stimulate photosynthetic physiology, upregulate carbon metabolism gene expression, and increase fruit yield in ‘Golden’ papaya while outperforming conventional NPK fertilization. A 12-month field experiment was conducted in a randomized complete block design with a factorial arrangement of four HS doses (0, 90, 180, and 270 mL plant⁻¹) combined with two FC doses (0 and 60 kg plant⁻¹) plus an NPK control, measuring photosynthetic pigments, gas exchange, relative expression of rbcL, ACC oxidase, invertase, relative growth rate, and fruit yield. Combined HS and FC increased chlorophyll a by up to 205%, chlorophyll b by 277%, and carotenoids by 208% relative to unamended controls. Gene expression was strongly induced: rbcL reached 202-fold, invertase 156-fold, and ACC oxidase 84.8-fold above control values. Photosynthetic rate followed a quadratic dose-response peaking near 90 mL plant⁻¹ HS. Fruit yield nearly doubled under the optimal combined treatment (115 t ha⁻¹) compared with unamended controls (62 t ha⁻¹) and NPK fertilization (66 t ha⁻¹). These results confirm that HS and FC act synergistically as dual-purpose amendments, improving soil fertility while biostimulating papaya physiology through coordinated upregulation of photosynthetic capacity and carbon partitioning toward reproductive sinks. Full article

The utilization of sugarcane molasses as a low-cost carbon source for riboflavin production is hindered by the reactive oxygen species (ROS) stress induced by its complex components, which suppresses microbial metabolism. To address this, we employed adaptive laboratory evolution (ALE) under progressively increasing stress to develop a sugarcane molasses-tolerant and high-yielding Ashbya gossypii. The adapted strain achieved a riboflavin titer of 298.39 ± 2.01 mg/L, representing a 99.4% increase over the parental strain (149.66 ± 4.97 mg/L), accompanied by a 96% increase in biomass (dry cell weight). Notably, the specific riboflavin production per unit biomass showed no significant difference between the two strains, indicating that the improved total yield was primarily driven by enhanced biomass accumulation. Transcriptomic analysis revealed the molecular basis for this enhanced biomass accumulation—the elevated expression of antioxidant enzymes (SOD1, PRDX5) mitigated ROS levels to support cellular growth, while the coordinated upregulation of the pentose phosphate pathway (E2.2.1.1) and purine metabolism genes (PPAT, ADE5, PFAS, ADSL) enhanced the supply of biosynthetic precursors, ribulose-5-phosphate (Ru5P) and GTP, for nucleotide biosynthesis and cell proliferation. These metabolic adjustments collectively enabled the adapted strain to achieve robust growth under sugarcane molasses stress, thereby driving the overall increase in riboflavin production. This study elucidates the molecular mechanism underlying ALE-improved riboflavin production and provides a promising strategy for its industrial fermentation using sugarcane molasses. Full article

The economic viability of second-generation (2G) bioethanol production depends on the availability of robust, multistress-tolerant yeast strains capable of withstanding harsh industrial conditions. This study investigates animal manure as a novel ecological niche for discovering such strains, as microbes in these environments naturally adapt to high organic loading and fluctuating temperatures. From eighty-six initial isolates, twenty-nine demonstrated superior xylose fermentation at 37 °C. Eight high-performing isolates (C2-1, B1-2, B1-6, B2-6, B2-8, G1-4, G1-5, and G2-4) exhibited exceptional tolerance to ethanol, high temperatures, and lignocellulosic-derived inhibitors (acetic acid, formic acid, furfural, and vanillic acid). Molecular identification classified isolate C2-1 as Pichia kudriavzevii and the remaining seven as Candida tropicalis. In synthetic media, C. tropicalis B2-8 produced up to 16.33 g/L of ethanol using xylose (60 g/L) as the sole carbon source. While the undetoxified, highly acidic sugarcane bagasse hydrolysate completely inhibited yeast growth, the industrial potential of these strains was successfully validated using the concentrated, undetoxified enzymatic hydrolysate derived from the acid-pretreated sugarcane bagasse solids, which contained 30.15 g/L glucose and 25.58 g/L xylose. P. kudriavzevii C2-1 achieved ethanol titers of 6.02 g/L and 5.71 g/L at 37 °C and 40 °C, respectively. The C. tropicalis strains outperformed P. kudriavzevii, yielding 6.12–6.35 g/L at 37 °C and maintaining 5.75–6.19 g/L at 40 °C. These findings underscore the potential of manure-derived yeasts as resilient biocatalysts. Although their fermentation yields remain relatively low and require further metabolic optimization, their ability to survive and ferment in this concentrated, undetoxified enzymatic hydrolysate at elevated temperatures makes them promising candidates for further development in high-temperature ethanol fermentation (HTEF), offering a potential pathway toward reducing cooling costs associated with 2G biorefineries. Full article

The improvement of sucrose yield in sugarcane is impeded by the crop’s complex polyploid genome and slow progress in breeding. To clarify how arginine (Arg) regulates sugar metabolism and identify key genes associated with sucrose transport and accumulation in sugarcane, a screening experiment was performed by spraying L-arginine hydrochloride on the leaves and leaf sheaths of three sugarcane varieties (YZ05-51, YZ08-1609, and YT93-159), which differ in growth vigor, leaf morphology and other phenotypic traits. YZ05-51 exhibited the most prominent sugar-increasing effect, and subsequent optimization experiments on its leaf sheaths revealed that 20 g/mu L-arginine hydrochloride at pH 7.0 was optimal, significantly enhancing stem sucrose content. Transcriptomic analysis revealed the upregulation of genes related to sucrose synthesis and transport, with candidate genes enriched in pathways such as starch-sucrose metabolism, glycolysis/gluconeogenesis, and ATP-binding cassette (ABC) transporters. Metabolomic analysis detected 32 sugar metabolites across three categories, of which 24 were differentially abundant (e.g., glucose, galactose, fructose, and mannose). Integrated multi-omics analysis identified key regulatory genes, including SBEs and TPS1 (sucrose synthesis and carbon flux regulation), RBSK, α-amylases, GH28 (starch breakdown, glycolysis, and sugar mobilization), ABC transporters, GTs, and TIM10/TIM12 (sucrose transporter). Collectively, these analyses demonstrate enhanced activity of genes and metabolites involved in sucrose synthesis/transport in leaf sheaths, accompanied by reduced synthesis of other monosaccharides and oligosaccharides. Vigorously metabolizing leaf sheaths is more conducive to sucrose transport. This study provides valuable insights into the molecular mechanisms underlying Arg-mediated sucrose accumulation specifically in the sugarcane YZ05-51 sugarcane, highlighting its critical regulatory roles. Full article

The red macroalga Kappaphycus alvarezii, widely cultivated for carrageenan extraction, has emerged as a promising blue economy resource of bioactive compounds for sustainable agriculture. However, knowledge regarding the composition, mechanisms of action, agronomic effects, and large-scale applicability of K. alvarezii-based products remains fragmented. Therefore, this review provides an overview of the potential of K. alvarezii and its by-products for the development of agricultural bioinputs, addressing species diversity, cultivation practices, chemical characterization of bioactive compounds, and their agronomic applications. Literature evidence indicates that K. alvarezii biomass is rich in sulfated polysaccharides, phenolic compounds, photoprotective pigments, fatty acids, and metabolites with hormone-like activity, which have been associated with enhanced plant growth, increased photosynthetic efficiency, and improved tolerance to biotic and abiotic stresses, resulting in productivity gains in crops such as rice, maize, sugarcane, soybean, and vegetables. In addition, biomass represents a potential source of potassium and micronutrients that can complement conventional fertilization. Recent technological advances, as well as regulatory aspects and challenges related to the integration of these products into the global agricultural market, are also discussed. Overall, the evidence highlights the potential of K. alvarezii as a renewable resource for the development of innovative agricultural bioinputs, as biofertilizers and plant biostimulants. Full article

Sugarcane (Saccharum officinarum L.) is one of the world’s most important agro-industrial crops, and the technological quality of its juice directly determines the efficiency of sucrose extraction and recovery processes. In tropical soils with low P availability, conventional fertilization is often inefficient due to nutrient immobilization, which increases production costs and environmental risks. In this regard, plant growth-promoting bacteria (PGPBs) have emerged as a sustainable alternative to improve nutrient use efficiency. This study evaluated the effect of inoculation with A. brasilense, P. fluorescens, and B. subtilis (single strains and consortia), combined with two levels of residual p (160 and 225 kg P₂O₅·ha⁻¹), on the technological quality of the juice and the microbial dynamics of the rhizosphere. The experiment was conducted under tropical field conditions using a randomized complete block design with split plots and five replications. A highly significant interaction between phosphorus and inoculation (p < 0.001) was observed for °Brix, Pol, purity, and sucrose. The B. subtilis + P. fluorescens consortium under reduced phosphorus (160 kg P₂O₅·ha⁻¹) achieved the highest values for sucrose (17.26%), °Brix (20.32), and purity (87.03%). A linear regression model showed that rhizosphere microbial density explained a large proportion of the variability in sucrose (R² = 0.96; β = 2.02; p < 0.001). Principal component analysis explained 91.8% of the total variance, clearly separating the consortia from the individual strains and the controls. These results indicate that PGPB consortia, combined with moderate pH fertilization, can improve the technological quality of sugarcane while enhancing rhizosphere functionality, representing a promising strategy for more sustainable production systems in tropical environments. Full article

The phytophagous mite Schizotetranychus sacharum has caused population outbreaks in sugarcane crops in several regions of São Paulo State, Brazil, representing a potential phytosanitary risk due to its presence in commercial fields. However, knowledge of biological development and reproductive modes of S. sacharum remains limited. Therefore, this study aimed to characterize development, reproduction, and demographic parameters of S. sacharum on sugarcane leaves under laboratory conditions using Twosex-MSChart software, Version v6. Egg incubation lasted 5.25 ± 0.17 days, followed by larval (1.79 ± 0.07 days), protonymph (2.07 ± 0.05 days), and deutonymph (3.21 ± 0.12 days) stages, resulting in an egg-to-adult developmental period of 12.15 ± 0.30 days. The survival rate from egg to adult was 0.70. Mean longevity was 8.91 ± 0.64 days for males and 9.62 ± 0.37 days for females. Demographic parameters indicated an intrinsic rate of increase (r) of 0.080 day⁻¹, a finite rate of increase (λ) of 1.084 day⁻¹, and a mean generation time (T) of 17.35 days. Furthermore, S. sacharum exhibited both sexual and asexual reproduction. These findings contribute to understanding the biology and population growth potential of this species in sugarcane agroecosystems. Full article

Sugarcane is a globally important crop, widely cultivated for sugar production and bioenergy. However, leaf spot disease leads to a reduction in its quality and yield. In this study, pathogen identification, biological characteristic analysis, and screening of antagonistic bacteria against the causal pathogens were done as a basis for epidemic prediction and green control of sugarcane leaf spot disease. The causal pathogens of sugarcane leaf spot disease were identified as Epicoccum latusicollum El532 and Fusarium sacchari Fs64, respectively, based on morphological characteristics, multi-gene phylogenetic analysis (ITS, TUB2, and RPB2 for El532; ITS, TEF1α, and RPB2 for Fs64), and pathogenicity tests. Biological characterization revealed that both pathogens exhibited optimal mycelial growth at 25 °C and under continuous darkness. However, light-dark cycles inhibited their growth. The optimal pH ranges for both isolates were 6–9 and 5–10, respectively. Maltose was the optimal carbon source for El532, whereas maltose, lactose, and starch were optimal for Fs64. Yeast extract served as the optimal nitrogen source for both. Isolation and screening of bacterial strains from healthy sugarcane roots, leaves, and rhizosphere soil yielded 13 antagonistic bacterial strains. Among them, six strains exhibited inhibition rates exceeding 57% against both pathogens. Bacillus subtilis A5 exhibited the highest antagonistic activity (68.85% against El532, 71.69% against Fs64), underscoring its potential as a promising biocontrol candidate. These findings provide a scientific basis for the diagnosis and management of sugarcane leaf spot disease. Full article

Based on previous findings that fiber digestibility and rumen fermentation in weaned buffalo calves were improved by a roughage combination of dried sugarcane leaves (SDL) and peanut vine (PV), this study reveals that the mechanism for improving fiber digestibility and growth performance involves increasing Succiniclasticum abundance and 3-methoxytyramine-betaxanthin level, which consequently increases ruminal acetate and propionate. Twenty-one calves were fed pelleted diets with roughage combinations the 15% SDL combined with PV (S15PV, 15% SDL + 15% PV), the 22.5% SDL combined with PV (S22.5PV, 22.5% SDL + 7.5% PV), or the 30% SDL combined with PV (S30PV, 30% SDL) for 63 days. The results showed no significant differences in α-diversity and β-diversity among the three groups (p > 0.05). A significantly higher relative abundance of Succiniclasticum was observed in the S22.5PV group than in the other two groups, by 241.57% and 136.25%, respectively (p < 0.05), and its effects were primarily exerted through carbohydrate and amino acid metabolism pathways. Differential metabolites were mainly enriched in cofactor/vitamin metabolism (vitamin B6, riboflavin) and amino acid pathways (arginine, tryptophan). By PLS-DA analysis, significantly higher levels of Bentyl and 3-Methoxytyramine-betaxanthin were observed in the S22.5PV group compared to the S15PV and S30PV groups, respectively. Positive correlations were observed between Succiniclasticum and NDFD, ADFD, acetic acid, propionic acid, isovaleric acid, as well as 3-Methoxytyramine-betaxanthin (p < 0.05). In conclusion, the rumen microbial diversity was not altered by the roughage combinations of dried sugarcane leaves and peanut vine, but the abundance of Succiniclasticum and the level of 3-Methoxytyramine-betaxanthin were significantly correlated with NDFD and ADFD, which enriched ruminal AA and PA, and may thus be associated with improved growth performance. Full article

Weed interference during early growth stages is a major constraint on sugarcane productivity, yet effective tools for species-specific detection remain limited in tropical agricultural systems. This study evaluated the spectral separability between Sugarcane (Saccharum officinarum) and a dominant weed species, Rottboellia cochinchinensis, to develop an accessible framework for early-stage weed mapping. Multispectral data acquired from an Unmanned Aerial Vehicle (UAV) and hyperspectral data obtained from a field spectrometer were utilized. Hyperspectral data were synthesized to reconstruct multispectral bands (UAV image bands) using a regularized linear synthesis model, thereby generating spectral signatures. Spectral separability between sugarcane and Rottboellia cochinchinensis was assessed visually and statistically (Jeffries–Matusita distance). Blue and Green bands provided the strongest differentiation between species, while RedEdge enhanced separability when paired with pigment-sensitive wavelengths. When using vegetation indices based on the near-infrared (NIR) band, the visual appearance of class separation was poor due to the NIR band’s sensitivity to variation in leaf internal structure, canopy architecture, water content, and spectral mixing with the soil background at the early stage of sugarcane. These results were used to differentiate weed coverage from sugarcane. Object-based image analysis (OBIA) outperformed the pixel-based method, achieving higher overall accuracy (0.9038) and a more spatially coherent weed delineation (Kappa = 0.8499). These findings suggest that synthesized spectral signatures of Rottboellia cochinchinensis and sugarcane, combined with targeted spectral indices and OBIA techniques, offer a practical and transferable approach for early detection of Rottboellia cochinchinensis at the farm level. Full article

Sugarcane stores sucrose in a living culm for extended periods, yet the respiratory cost of maintaining this storage tissue remains poorly quantified. We quantified growth and maintenance respiration along the culm (internodes 1 to 12) in three genotypes at mid-season (rapid growth) and end-season (maturation) using a composition-based carbon accounting framework derived from measurements of biomass accumulation and composition. Growth respiration was highest in elongating internodes (3 to 6) and declined with maturation, whereas maintenance respiration increased progressively and dominated in mature storage internodes (10 to 12). Consequently, total sink demand remained substantial even after structural growth slowed, indicating that mature internodes continue to require significant metabolic input despite limited biomass production. To evaluate the potential impact of energetic constraints, we simulated reduced mitochondrial energy contribution to assess the sensitivity of respiratory carbon demand to decreased energetic efficiency. These simulations predicted an increase in glucose requirement for respiration across all internodes, with the largest proportional effect in mature tissue where maintenance costs dominated. Despite this predicted increase in respiratory demand, sucrose accumulation was maintained in mature culms, indicating that respiratory carbon loss remains constrained during storage. This suggests that storage tissue operates with relatively high carbon-use efficiency during maintenance-dominated metabolism. We interpret this pattern as consistent with metabolic configurations that reduce ATP demand, potentially involving partial substitution of ATP-dependent reactions by pyrophosphate (PPi)-dependent pathways, although this mechanism was not directly measured. These findings highlight the importance of maintenance respiration and energetic efficiency in determining sink strength and sucrose yield, and they provide a physiological framework for understanding carbon conservation in long-lived storage organs. Full article