Acetic Acid Production Research Articles

Melanoidin Content Determines the Primary Pathways in Glucose Dark Fermentation: A Preliminary Assessment of Kinetic and Microbial Aspects

Melanoidins are heterogeneous polymers with a high molecular weight and brown color formed during the Maillard reaction by the combination of sugars and amino acids at high temperatures with the potential to inhibit the microbial activity in bioprocesses. This study assessed the impacts of melanoidins on the kinetic of substrate conversion and production of organic acids via dark fermentation using microbial consortia as inoculum. The investigations were carried out in fed-batch reactors using synthetic melanoidins following glucose-to-melanoidin ratios (G/M; g-glucose g−1 melanoidins) of 0.50, 1.50, 1.62, 1.67, and 5.00, also considering a melanoidin-free control reactor. The results showed that melanoidins negatively impacted the kinetics of glucose fermentation by decreasing the first-order decay constant (k1): when dosing equivalent initial concentrations of glucose (ca. 3 g L−1), the absence of melanoidins led to a k1 of 0.62 d−1, whilst dosing 2 g L−1 (G/M = 1.5) and 6.0 g L−1 (G/M = 0.5) of melanoidins produced k1 values of 0.37 d−1 and 0.27 d−1, respectively. The production of butyric and acetic acids was also negatively impacted by melanoidins, whilst the lactic activity was not impaired by the presence of these compounds. Lactate production reached ca. 1000 mg L−1 in G/M = 1.67, whilst no lactate was detected in the control reactor. The presence of melanoidins was demonstrated to be a selective metabolic driver, decreasing the microbial diversity compared to the control reactor and favoring the growth of Lactobacillus. These results highlight the importance of further understanding the impacts of melanoidins on melanoidin-rich organic wastewater bioconversion, such as sugarcane vinasse, which are abundantly available in biorefineries.

Interactive Effects of Dietary Fiber and Lipid Types Modulate the Predicted Production and Absorption of Cecal and Colorectal Short-Chain Fatty Acids in Growing Pigs

BackgroundHigh-fiber diets are supplemented with lipids to meet the required energy content, but data on the interactions between dietary fiber (DF) and lipid types on gastrointestinal fermentation in pigs are scant. ObjectivesThis study aimed to use a combination of in vivo and in vitro fermentation methodologies to determine the interactive effects of DF and lipid types on short-chain fatty acid (SCFA) production and absorption and organic matter (OM) fermentability in the cecum and colorectal tract of pigs. MethodsEight ileal- and cecal-cannulated Yorkshire barrows were fed either pectin- or cellulose-containing diets that were supplemented with either corn oil or beef tallow in 2 independent Youden squares with a 2 × 2 factorial arrangement of treatments (n = 6). Ileal and cecal digesta were collected, freeze-dried, and fermented using inoculum from fresh cecal digesta and feces, respectively, to determine individual SCFA production and absorption and fermentability of OM. ResultsInteractions (P < 0.001) between DF and lipid types were observed in which the addition of beef tallow decreased the quantity of cecal and colorectal acetic acid production and cecal acetic absorption, cecal butyric production, predicted cecal OM fermentability, and predicted colorectal propionic acid in pectin diets, but the effects were not observed for cellulose diets. The addition of beef tallow increased (P < 0.001) the production of cecal butyric and propionic acids during in vitro fermentation in cellulose diets and apparent total tract digestibility (ATTD) of OM in pectin diets. ConclusionsThe interactions between DF and lipids on gastrointestinal fermentation largely depend on the degree of saturation of fatty acids in dietary lipids. The addition of beef tallow selectively decreased the production and absorption of individual SCFAs in pectin and cellulose diets but increased cecal butyric and propionic acid production in cellulose diets and the ATTD of OM in pectin diets.

Isolation, screening, and characterization of the newly isolated osmotolerant yeast Wickerhamomyces anomalus BKK11-4 for the coproduction of glycerol and arabitol.

This study explored the isolation and screening of an osmotolerant yeast, Wickerhamomyces anomalus BKK11-4, which is proficient in utilizing renewable feedstocks for sugar alcohol production. In batch fermentation with high initial glucose concentrations, W. anomalus BKK11-4 exhibited notable production of glycerol and arabitol. The results of the medium optimization experiments revealed that trace elements, such as H3BO3, CuSO4, FeCl3, MnSO4, KI, H4MoNa2O4, and ZnSO4, did not increase glucose consumption or sugar alcohol production but substantially increased cell biomass. Osmotic stress, which was manipulated by varying initial glucose concentrations, influenced metabolic outcomes. Elevated glucose levels promoted glycerol and arabitol production while decreasing citric acid production. Agitation rates significantly impacted the kinetics, enhancing glucose utilization and metabolite production rates, particularly for glycerol, arabitol, and citric acid. The operational pH dictated the distribution of the end metabolites, with glycerol production slightly reduced at pH 6, while arabitol production remained unaffected. Citric acid production was observed at pH 6 and 7, and acetic acid production was observed at pH 7. Metabolomic analysis using GC/MS identified 29 metabolites, emphasizing the abundance of sugar/sugar alcohols. Heatmaps were generated to depict the variations in metabolite levels under different osmotic stress conditions, highlighting the intricate metabolic dynamics occurring post-glucose uptake, affecting pathways such as the pentose phosphate pathway and glycerolipid metabolism. These insights contribute to the optimization of W. anomalus BKK11-4 as a whole-cell factory for desirable products, demonstrating its potential applicability in sustainable sugar alcohol production from renewable feedstocks.

Intervention with fructooligosaccharides, Saccharomyces boulardii, and their combination in a colitis mouse model.

To examine the effects of an intervention with fructooligosaccharides (FOS), Saccharomyces boulardii, and their combination in a mouse model of colitis and to explore the mechanisms underlying these effects. The effects of FOS, S. boulardii, and their combination were evaluated in a DSS-induced mouse model of colitis. To this end, parameters such as body weight, the disease activity index (DAI), and colon length were examined in model mice. Subsequently, ELISA was employed to detect the serum levels of proinflammatory cytokines. Histopathological analysis was performed to estimate the progression of inflammation in the colon. Gas chromatography was used to determine the content of short-chain fatty acids (SCFAs) in the feces of model mice. Finally, 16S rRNA sequencing technology was used to analyze the gut microbiota composition. FOS was slight effective in treating colitis and colitis-induced intestinal dysbiosis in mice. Meanwhile, S. boulardii could significantly reduced the DAI, inhibited the production of IL-1β, and prevented colon shortening. Nevertheless, S. boulardii treatment alone failed to effectively regulate the gut microbiota. In contrast, the combined administration of FOS/S. boulardii resulted in better anti-inflammatory effects and enabled microbiota regulation. The FOS/S. boulardii combination (109 CFU/ml and 107 CFU/ml) significantly reduced the DAI, inhibited colitis, lowered IL-1β and TNF-α production, and significantly improved the levels of butyric acid and isobutyric acid. However, FOS/S. boulardii 109 CFU/ml exerted stronger anti-inflammatory effects, inhibited IL-6 production and attenuated colon shortening. Meanwhile, FOS/S. boulardii 107 CFU/ml improved microbial regulation and alleviated the colitis-induced decrease in microbial diversity. The combination of FOS and S. boulardii significantly increased the abundance of Parabacteroides and decreased the abundance of Escherichia-Shigella. Additionally, it promoted the production of acetic acid and propionic acid. Compared with single administration, the combination can significantly increase the abundance of beneficial bacteria such as lactobacilli and Bifidobacteria and effectively regulate the gut microbiota composition. These results provide a scientific rationale for the prevention and treatment of colitis using a FOS/S. boulardii combination. They also offer a theoretical basis for the development of nutraceutical preparations containing FOS and S. boulardii.

Characterization and Field Evaluation of Potential Fluorescent Pseudomonas Isolates on Growth and Yield Attributing Characters in Chickpea

The present investigation was conducted at the research and instructional farm, College of Agriculture, Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, India during rabi (October–December 2019) to evaluate the influence of fluorescent Pseudomonas isolates on chickpeas through characterization and field evaluation. Eighty-eight rhizosphere soil samples were derived from different locations in Bastar and Bilaspur districts of Chhattisgarh, India. Potential isolates were required for fundamental research and practical application of plant growth-promoting rhizobacterial strains on different crops. Among eighty-eight isolates, ten fluorescent Pseudomonas (visible under UV light at 360 nm) emitting strong fluorescence were selected for the course of the investigation and characterized for the production of siderophores, phosphate solubilization, indole acetic acid, 1-aminocyclopropane-1-carboxylic acid deaminase, and analysis of antagonistic potential. Of the 10 Pseudomonas isolates, 9704 was identified as the highest phosphate solubilizer, BSP-23 was identified as the highest indole acetic acid producer, and BSP-19 was the highest siderophore producer. Fluorescent Pseudomonas isolates BS-1, BS-4, 9809, BSP-14, and BSP-19 were identified to possess 1-aminocyclopropane-1-carboxylic acid deaminase-producing ability following qualitative analysis. Our present investigation indicates that beneficial effects of fluorescent Pseudomonas could be achieved through simple and cost-effective seed treatment. Three fluorescent Pseudomonas strains, 9704, BS-14, and 9829, consistently increased seed germination and improved plant growth and yield (BS-37.9% and 9704-35.7%) attributes in chickpeas. Besides, confrontation assays performed against R. bataticola expressed varying levels of inhibition. The phylogenetic affinities of 16S rRNA gene sequencing resolved the species identities of selected isolates.

Structural characterization and prebiotic activity of rhamnogalacturonan-I rich pumpkin pectic polysaccharide extracted by alkaline solution

The present study aimed to investigate the structural and physicochemical characteristics of alkali-extracted pectic polysaccharide (AkPP) and to evaluate its prebiotic effects. AkPP was obtained from pumpkin pulp using an alkaline extraction method. AkPP, which had a molecular weight (Mw) of mainly 13.67 kDa and an esterification degree of 9.60%, was composed mainly of galacturonic acid (GalA), rhamnose (Rha), galactose, and arabinose. The ratio of the homogalacturonan (HG) region to the rhamnogalacturonan-I (RG-I) region in AkPP was 48.74:43.62. In the nuclear magnetic resonance spectrum, the signals indicating α-1,4-linked D-GalA, α-1,2-linked L-Rha, α-1,2,4-linked L-Rha residues were well resolved, demonstrating the presence of the HG and RG-I regions in its molecular structure. Collectively, AkPP was low methoxyl pectin rich in the RG-I region with short side chains and had a low Mw. Thermal analysis revealed that AkPP had good thermal stability. Compared to inulin, AkPP more effectively promoted the proliferation of Lactobacillus acidophilus, Lacticaseibacillus rhamnosus GG, Lacticaseibacillus casei, and Lacticaseibacillus paracasei and the production of lactic, acetic, and propionic acids. This study presents the unique structural features of AkPP and provides a scientific basis for further investigation of the potential of AkPP as a promising prebiotic.

Supplementation with soluble or insoluble rice-bran fibers increases short-chain fatty acid producing bacteria in the gut microbiota in vitro.

Studies have shown that a diet high in fiber and prebiotics has a positive impact on human health due largely to the fermentation of these compounds by the gut microbiota. One underutilized source of fiber may be rice bran, a waste product of rice processing that is used most frequently as an additive to livestock feed but may be a good source of fibers and other phenolic compounds as a human diet supplement. Previous studies focused on specific compounds extracted from rice bran showed that soluble fibers extracted from rice bran can improve glucose response and reduce weight gain in mouse models. However, less is known about changes in the human gut microbiota in response to regular rice bran consumption. In this study, we used a Simulator of the Human Intestinal Microbial Ecology (SHIME®) to cultivate the human gut microbiota of 3 different donors in conditions containing either soluble or insoluble fiber fractions from rice bran. Using 16S rRNA amplicon sequencing and targeted metabolomics via Gas Chromatography-Mass Spectrometry, we explored how gut microbial communities developed provided different supplemental fiber sources. We found that insoluble and soluble fiber fractions increased short-chain fatty acid production, indicating that both fractions were fermented. However, there were differences in response between donors, for example the gut microbiota from donor 1 increased acetic acid production with both fiber types compared with control; whereas for donors 2 and 3, butanoic acid production increased with ISF and SF supplementation. Both soluble and insoluble rice bran fractions increased the abundance of Bifidobacterium and Lachnospiraceae taxa. Overall, analysis of the effect of soluble and insoluble rice bran fractions on the human in vitro gut microbiota and the metabolites produced revealed individually variant responses to these prebiotics.

Dynamics of microbial ecology and their bio-preservative compounds formed during the panettones elaboration using sourdough-isolated strains as starter cultures

The present study evaluated the application of Limosilactobacillus fermentum IAL 4541 and Wickerhamomyces anomalus IAL 4533 isolated from sourdoughs and their combinations, for bio-conservative action in panettones, as well as to identify the antifungal volatile compounds. Samples from different fermentation steps were submitted to physicochemical and microbiological evaluation, as to know: sourdough after 48 h (A), 96 h (B), and 144 h (C); dough of the first fermentation (D); final dough after second fermentation (E), and baked panettone (F). In all treatments, lactic bacteria and yeast counts demonstrated a mechanism of proto-cooperation. Panettones containing L. fermentum or W. anomalus in their composition had longer shelf life, which indicates their effect as potential biopreservatives. The genetic sequencing data demonstrated the dominance of the Lactobacilli throughout the process, corroborating the data obtained by cultivable methods. A total of 59 volatile organic compounds were found in this study, and a hierarchical cluster analysis presented the separation between the production stages (C, E) and the most recurrent compounds in the final product (F). Of these compounds, the following stood out (n = 26): acids (7.7%), alcohols (23.1%), aldehydes and ketones (34.6%), and esters (34.6%). The treatments containing L. fermentum presented more diversity of volatile organic compounds with potential antifungal effect. There was a higher production of acetic (1.17–8.85 mmol/kg), phenyllactic (5–10.4 mmol/kg), and propionic (3.5–4.3 mmol/kg) acids in the final product. This study demonstrates the feasibility of applying endogenous starter cultures from sourdoughs, with great biopreservative activity, enabling the production of healthier and more natural panettones.

Adaptable heat pump-assisted dividing-wall column design for intensified downstream processing of bio-propionic acid

Propionic acid is a valuable platform chemical that is usually produced via fossil routes. As these are energy-intensive and eco-unfriendly processes, fermentative production of propionic acid is becoming more attractive. However, the complex downstream processing (due to low achievable product concentrations, high water content, presence of by-products and thermodynamic constraints), presents a potential barrier to scale-up this technology. This original research proposes a novel intensified large-scale (production capacity of ∼ 20 ktonne/y) process for the final recovery of propionic acid after the initial biomass and counterion removal. Vacuum distillation steps ensure the recovery of a high-purity succinic acid product (>99.9 wt%) and a water stream that may be recycled to the fermentation to reduce the fresh water requirements. The main unit that follows is a highly integrated heat pump-assisted dividing-wall column (DWC), which allows the effective separation of propionic (>99.9 wt%) and acetic acid (99.4 wt%) products. Alternatively, it can serve as a reactive DWC that performs the esterification and separation of methyl propionate (99.8 wt%), methyl acetate (91.0 wt%) as higher added value products, and water by-product. If needed, extractive distillation can be implemented additionally to recover methyl acetate at higher purity (99.9 wt%). Overall, both options are proven to be economically interesting (recovery costs of 0.399 – 0.469 $/kg considering the product price of 1.349 – 1.802 $/kg) and environmentally attractive (3.206 – 3.678 kWthh/kg).

DIAZOTROPHIC ENDOPHYTE Klebsiella sp. N5 FROM SORGHUM SHOWS CROSS-COLONIZATION AND PLANT GROWTH PROMOTION IN RICE

Rice necessitates the highest levels of N fertilizers during its cultivation increasing demand for nitrogen fertilizers as well as negatively affecting the environment. Endophytic diazotrophic bacteria were isolated from sorghum, out of 35 isolates Klebsiella sp. N5 showed maximum potential for biological nitrogen fixation. Primary screening of strain N5 was done with acetylene reduction assay indicating dry root activity of 638.55 nmol C2H4 h-1 g-1. That was further confirmed by nifH gene amplification. The strain was identified morphologically, biochemically and 16S rDNA sequencing analysis and identified as Klebsiella sp. strain N5. This strain exhibited other plant growth-promoting (PGP) traits, such as phosphate solubilization, production of indole acetic acid, siderophore activity, ACC deaminase activity, and anti-fungal activity. PGP endophyte N5 was inoculated into rice seedlings to investigate its interaction under axenic conditions and to characterize its ability to colonize non-native host plant rice. Extensive colonization of rice roots was corroborated by Scanning electron microscopy. In-planta experiments with rice seeds inoculated with Klebsiella sp. N5 showed significant improvements in various agronomic traits such as increase in shoot length, root length, fresh and dry weight of root and shoot, chlorophyll content, and nitrogen content of the plant and soil compared to the untreated plants. Klebsiella sp. N5, a cross colonizer from sorghum (C4 plant) to rice (C3 plant) plays a crucial role in facilitating the acquisition of essential resources such as nitrogen, phosphorus, and iron through direct mechanisms. This study expands the horizon for its potential as a valuable bioinoculant for sustainable agricultural practices, particularly in non-native host rice, paving the way for future field trials.

Occurrence of Sphingomonas olei with elemental S oxidation capability in sodic soil: Potential role in sodicity reclamation and plant growth promotion

The success of the sodic soil reclamation using elemental S (S°) depends on the population of the native S° oxidizers. Augmenting the native flora of the sodic soils with effective S° oxidizers can enhance the success of the sodic soil reclamation. Present study reports for the first time the S° oxidation potential of the Sphingomonas olei strain 20UP7 isolated from sodic soils with pHs 9.8 and ECe 3.6 dS m–1. Inoculation with S. olei strain 20UP7 caused 13.0–24.2 % increase in S° oxidation in different sodic soils (pHs 9.1–10.5). It improved the concentration of the Ca2+, Mg2+, PO43– and declined the HCO3– and total alkalinity of the soil solution. This isolate also showed appreciable P and Zn solubilization, indole acetic acid, ammonia, and titratable acidity production in the growth media. It tended to the formation of biofilm around sulphur particles. The PCR amplification with gene–specific primers showed the occurrence of soxA, soxB, and soxY genes with a single band corresponding to length of 850, 460, and 360 base pairs, respectively. The integration of the S. olei strain 20UP7 with S° caused 21.7–25.4 % increase in the rice and wheat yield compared to the soil treated with S° alone. This study concludes that the S. olei, native to high saline–sodic soils can be utilized for improving the sodicity reclamation and plant growth promotion using elemental S based formulations.

Studies on the Impact of Microbial Consortia towards Enhancing the Growth of Red Sanders

The use of plant growth-promoting microorganisms, either alone or combined, as bioinoculants presents an economical and eco-friendly alternative to chemical fertilizers. This method provides a comprehensive solution for enhancing plant growth and yield. This study aimed to develop robust microbial consortia possessing plant growth-promoting capabilities and evaluate their effectiveness in enhancing tree seedling growth. Six bacterial strains were collected and screened for specific traits linked to promoting plant growth. Selected strains were then assessed for compatibility with each other, resulting in the formation of bacterial consortia. These consortia demonstrated diverse plant growth-promoting properties, including the production of the plant growth hormone indole acetic acid and the synthesis of exopolysaccharides. Consequently, these bacterial consortia exhibit significant potential as bioinoculants, offering a promising approach to enhancing plant growth and productivity in an environmentally friendly manner. This contributes to the progress of efforts aimed at promoting seedling growth.

Effects of yak rumen anaerobic fungus Orpinomyces sp. YF3 fermented on in vitro wheat straw fermentation and microbial communities in dairy goat rumen fluid, with and without fungal flora.

Rumen fungi play an essential role in the breakdown of dietary fibrous components, facilitating the provision of nutrients and energy to the host animals. This study investigated the fermentation characteristics and effects on rumen microbiota of yak rumen anaerobic fungus Orpinomyces sp. YF3 in goat rumen fluid, both with and without fungal flora, utilizing anaerobic fermentation bottles. Crushed and air-dried wheat straw served as the fermentation substrate, and cycloheximide was used to eradicate microorganisms from the rumen fluid of dairy goats. The experiment compromised four treatment groups (2×2 factorial design): control (C); yak fungus group (CF, Orpinomyces sp. YF3); goat fungi eliminated group (CA, antibiotic: 0.25 mg/mL cycloheximide); goat fungi eliminated+yak fungus group (CAF). Each treatment had six replicates. Fermentation characteristics and microbial composition of the fermentation media were analyzed using one-way analysis of variance and high-throughput sequencing technology. The findings revealed that in the Orpinomyces sp. YF3 addition group (CF and CAF groups), there were significant increases in ammonia nitrogen concentration by 70%, total volatile fatty acids (VFA) by 53%, as well as acetate, isobutyrate, and valerate concentrations, and the ratio of acetate to propionate (p < 0.05), while the propionate proportion declined by 13%, alongside a reduction of butyrate concentration (p < 0.05). Similarly, in the CF and CAF groups, there were a notable increase in the relative abundance of Bacteroidota, Synergistota, Desulfobacterota, Actinobacteria, and Fusobacteriota, alongside a decrease in the relative abundance of Fibrobacterota and Proteobacteria (p < 0.05). Bacteria exhibiting increased relative abundance were positively correlated with the activity of carboxymethyl cellulase and avicelase, total VFA concentration, and acetate proportion, while showing a negatively correlation with propionate proportion. In conclusion, supplementing rumen fermentation media with yak rumen anaerobic fungus Orpinomyces sp. YF3 led to an increase in bacteria associated with fibre degradation and acetic acid production, a decrease in propionate-producing bacteria, enhanced the activity of plant cell wall degrading enzymes, and promoted cellulose degradation, ultimately elevating total VAF concentration and acetate proportion. This presents a novel approach to enhance roughage utilization in ruminants.

A sustainable bioprocessing system leveraging gas fermentation and bipolar membrane electrodialysis system for direct recovery of acetic acid

This study examined the integration of gas fermentation with bipolar membrane electrodialysis (BPMED) for sustainable production of acetic acid and bases, focusing on medium recycling and ion-exchange membrane optimisation. Gas fermentation was performed using an acetogenic microbe, Eubacterium callanderi KIST612, in a custom-designed gas bioreactor. The BPMED system was operated under specific voltage conditions to evaluate the proton and hydroxyl ion generation, ion concentration, and residual ratios. Gas fermentation consistently generated acetate with a stable CO2 consumption rate (0.167 mmol gcell−1) and an increased rate of conversion of carbon into biochemicals via methanol. The BPMED system efficiently produced acetic acid (acetate extraction rate of 99.72 %–99.82 %) and hydroxide ions (from 8 to 18 V), with operational challenges identified at higher voltage levels (≥20 V). The BPMED process, which includes additional membranes and exhibits a lower acetate flux than the ED process, had remarkable cost-effectiveness, surpassing the ED integration process by 17.6 %. This economic advantage was paralleled by a significant environmental benefit, where the BPMED process reduced carbon dioxide emissions by 7.4 % compared with the ED process. These results suggest that integrating gas fermentation with BPMED is a viable and sustainable approach for acetic acid production.

Bifunctional enzyme-mimicking metal-organic frameworks for sensitive acetylcholine analysis

The development of nanomaterials with multi-enzyme-like activity is crucial for addressing challenges in multi-enzyme-based biosensing systems, including cross-talk between different enzymes and the complexities and costs associated with detection. In this study, Pt nanoparticles (Pt NPs) were successfully supported on a Zr-based metal-organic framework (MOF-808) to create a composite catalyst named MOF-808/Pt NPs. This composite catalyst effectively mimics the functions of acetylcholinesterase (AChE) and peroxidase (POD). Leveraging this capability, we replaced AChE and POD with MOF-808/Pt NPs and constructed a biosensor for sensitive detection of acetylcholine (ACh). The MOF-808/Pt NPs catalyze the hydrolysis of ACh, resulting in the production of acetic acid. The subsequent reduction in pH value further enhances the POD-like activity of the MOFs, enabling signal amplification through the oxidation of a colorimetric substrate. This biosensor capitalizes on pH variations during the reaction to modulate the different enzyme-like activities of the MOFs, simplifying the detection process and eliminating cross-talk between different enzymes. The developed biosensor holds great promise for clinical diagnostic analysis and offers significant application value in the field.

Screening and Optimization of IAA Production by PGPR isolated from Rhizosphere of a Pterocarpus marsupium Roxb. and their Effect on Plant Growth

Indole Acetic Acid (IAA) production is important attribute of PGPR that promote plant growth and development. The rhizosphere is hotspot in the soil that harbors PGPR. The present study was aimed with isolation and screening of IAA producing bacteria from the rhizosphere of Pterocarpus marsupium Roxb. Optimum culture conditions (pH, temperature, incubation period and L-tryptophan concentration for IAA production were studied for selected isolates and their effect on wheat growth and root development was evaluated. Among twenty four IAA producing isolates five isolates (Et1, Rp1, Rp5, Rp6, and Rp9) produced maximum IAA in range of 50-70 μg/mL and was used in optimization studies. Maximum IAA was produced in 96 hours of incubation, at pH 7 and with 0.1mg/mL of L-tryptophan by all five isolates. 30oC is the most suitable temperature for Et1, Rp1, Rp5, Rp9; whereas Rp6 produced nearly same amount of IAA at wide range of temperature 30-35oC (77-84.12 μg/mL) and at pH 7-8 ( 73-74μg/mL). Out of the five isolates, Rp6 exhibits the highest potential, having a maximum IAA of 84.12 μg/mL at 35°C and pH 7. Although tryptophan influences IAA synthesis but at higher concentration of tryptophan inhibits IAA synthesis. To validate the production of IAA, crude extracts were analyzed using thin layer chromatography (TLC). A spot of standard IAA with the same Rf value (0.91) was found to match a specific spot from the crude IAA.

Uncovering the secret weapons of an invasive plant: The endophytic microbes of Anthemis cotula

Understanding plant-microbe interaction can be useful in identifying the microbial drivers of plant invasions. It is in this context that we explored the diversity of endophytic microbes from leaves of Anthemis cotula, an annual plant that is highly invasive in Kashmir Himalaya. We also tried to establish the role of endophytes in the invasiveness of this alien species. We collected and processed leaf samples from three populations at three different sites. A total of 902 endophytic isolates belonging to 4 bacterial and 2 fungal phyla were recovered that belonged to 27 bacterial and 14 fungal genera. Firmicutes (29.1%), Proteobacteria (24.1%), Ascomycota (22.8%) and Actinobacteria (19%) were dominant across all samples. Plant growth promoting traits, such as Ammonia production, Indole Acetic Acid (IAA) production, Phosphate solubilization and biocontrol activity of these endophytes were also studied and most of the isolates (74.68%) were positive for ammonia production. IAA production, phosphate solubilization and biocontrol activity was present in 39.24%, 36.70% and 20.26% isolates, respectively. Furthermore, Botrytis cinerea, a pathogen of A. cotula in its native range, though present in Kashmir Himalaya does not affect A. cotula probably due to the presence of leaf endophytic microbial antagonists. Our results highlight that the beneficial plant growth promoting interactions and enemy suppression by leaf endophytes of A. cotula, may be contributing to its survival and invasion in the Kashmir Himalaya.

Bifidobacterium longum K5 Prevents Enterohaemorrhagic Escherichia coli O157:H7 Infection in Mice through the Modulation of the Gut Microbiota.

Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a commonly encountered foodborne pathogen that can cause hemorrhagic enteritis and lead to hemolytic uremic syndrome (HUS) in severe cases. Bifidobacterium is a beneficial bacterium that naturally exists in the human gut and plays a vital role in maintaining a healthy balance in the gut microbiota. This study investigated the protective effects of B. longum K5 in a mouse model of EHEC O157:H7 infection. The results indicated that pretreatment with B. longum K5 mitigated the clinical symptoms of EHEC O157:H7 infection and attenuated the increase in myeloperoxidase (MPO) activity in the colon of the mice. In comparison to the model group, elevated serum D-lactic acid concentrations and diamine oxidase (DAO) levels were prevented in the K5-EHEC group of mice. The reduced mRNA expression of tight junction proteins (ZO-1, Occludin, and Claudin-1) and mucin MUC2, as well as the elevated expression of virulence factors Stx1A and Stx2A, was alleviated in the colon of both the K5-PBS and K5-EHEC groups. Additionally, the increase in the inflammatory cytokine levels of TNF-α and IL-1β was inhibited and the production of IL-4 and IL-10 was promoted in the K5-EHEC group compared with the model group. B. longum K5 significantly prevented the reduction in the abundance and diversity of mouse gut microorganisms induced by EHEC O157:H7 infection, including blocking the decrease in the relative abundance of Roseburia, Lactobacillus, and Oscillibacter. Meanwhile, the intervention with B. longum K5 promoted the production of acetic acid and butyric acid in the gut. This study provides insights into the use of B. longum K5 for developing probiotic formulations to prevent intestinal diseases caused by pathogenic bacterial infections.

Acetic Fermentation of Cagaita Pulp: Technological and Chemical Characteristics

The Brazilian Cerrado region has a rich plant diversity, with fruits that have peculiar and unique sensory characteristics. For these reasons, using these fruits for biotechnological production is a promising alternative, mainly to protect this biome from deforestation and degradation. The production of fermented acetic acid is an option to add value to native fruits and offer the market beverages with better nutritional quality and bioactive compounds. This work aimed to characterize fruits and to develop cagaita (Eugenia dysenterica DC.) acetic fermented beverage. The fruits were subjected to physical-chemical analyses in the first part. Subsequently, different treatments for fermentation were tested using two types of enzymes (amylase and pectinase), two subspecies of Saccharomyces cerevisiae yeast (UFLA CA11 and thermoresistant LNF Angel), and the chaptalization of the must with sucrose (16 °Brix). Alcoholic fermentation was carried out in an incubator with temperature control at 34 ± 1 °C. The pH, total soluble solids, titratable acidity, alcohol content, and density of the fermented products were monitored daily. The chaptalized must with amylase addition and thermoresistant yeast had the best performance during alcoholic fermentation, demonstrating that thermoresistant yeast is an economically advantageous and efficient alternative for the cagaita juice fermentation process. Subsequently, acetic fermentation was carried out using the slow method. Heat-resistant yeast without added enzymes was used to produce cagaita acetic fermented beverages within the parameters of the Brazilian legislation. Furthermore, phenolic compounds and antioxidant activity in the final product were observed. The work demonstrated the possibility of using cagaita fruits in biotechnological processes to produce new food products.

Reaction Mechanisms and Production of Hydrogen and Acetic Acid from Aqueous Ethanol Using a Rn-Sn/TiO2 Catalyst in a Continuous Flow Reactor

The catalytic reforming of bioethanol can produce green hydrogen (H2) and acetic acid (AcOH). In the present study, the conversion of aqueous ethanol (EtOH) over 4 wt%Ru-4 wt%Sn/TiO2 in a flow reactor was investigated at different temperatures at 0.1 MPa or at various pressures at 260 °C. The ethanol conversion was rather slow in liquid water, while the reactivity increased significantly when water was evaporated. Under gas-phase conditions at 0.1 MPa, the conversion rate increased with increasing reaction temperature, but the AcOH yield and H2 purity decreased due to by-production of CH4, CO, and CO2. The CH4 and CO generated by fragmentation of acetaldehyde (AA), an intermediate, were suppressed by increasing reaction pressure, although the formation of CH4 and CO2 generated from AcOH was pressure independent. Thus, the highest-pressure conditions in steam at a given reaction temperature are preferred for the production of pure H2. The initial step, EtOH → AA, was the rate-determining reaction, and the model experiments using AA as a substrate showed that the Cannizzaro reaction of two AA molecules to form EtOH and AcOH occurred preferentially. This oxidation system was confirmed to be effective at EtOH concentrations of up to 500 g/L in water.