Batch Culture Research Articles

Synergistic Effects of Mannan Oligosaccharides and Onion Peels on In Vitro Batch Culture Fermentation of High Concentrate and Forage Diets

The current study evaluated the effect of combining mannan oligosaccharide (MOS) and onion peel (OP) on ruminal in vitro total gas (GP), greenhouse gas emissions, dry matter and fiber fraction digestibility, partitioning factor (PF24; mg degradable DM per mL gas), microbial mass, and volatile fatty acids using two dietary substrates: high forage (HF) and high concentrate (HC) diets. The study was arranged as a 2 × 2 × 6 factorial design with two dietary substrates, two time points (6 and 24 h), and six treatments. The treatments included a control group with no MOS or OP administration and groups administered with 2% of a mixture containing MOS and OP in the following ratios: 1:0 (MOS), 0:1 (OP), 1:1 (MOS:OP), 1:2 (MOS:2OP), and 1:3 (MOS:3OP). No significant diet × treatment interactions were observed for any of the measured parameters. However, treatments decreased (p < 0.05) the undegraded portion of HC, and treatment × substrate interactions were significant (p < 0.05) for PF24 and microbial mass. The treatments in the HC diet produced higher GP (p < 0.001) at 6 h compared to the treatments in the HF diet. Administration of MOS:2OP to the HC diet increased GP at 24 h of incubation, while the lowest GP was observed with the OP in the HF diet. The administration of MOS, OP, and MOS:2OP to the HC diet decreased methane production at 24 h of incubation. Additionally, MOS:2OP and MOS:3OP increased (p < 0.001) degradable acid detergent fiber (dADF) in the HC diet at 6 h of incubation. Both OP and MOS:3OP decreased the degradability of acid detergent lignin in the HC diet (p < 0.001). The OP also resulted in the lowest DM disappearance (p < 0.001) at 24 h of incubation in the HF diet, while the MOS:3OP had the highest dADF. At the end of incubation, the highest productions of total volatile fatty acids and acetate were observed (p = 0.002) with the MOS:OP administration in the HC diet, whereas the lowest values were observed with MOS and OP administration to the HF diet. The inclusion of mannan oligosaccharide and onion peel combinations as additives improved substrate (HC and HF) fermentation, leading to higher GP and volatile fatty production, and modulated fiber degradability by improving the breakdown of acid detergent fiber and acid detergent lignin.

Simultaneous saccharification and fermentation for d-lactic acid production using a metabolically engineered Escherichia coli adapted to high temperature

BackgroundEscherichia coli JU15 is a metabolically engineered strain capable to metabolize C5 and C6 sugars with a high yield of d-lactic acid production at its optimal growth temperature (37 °C). The simultaneous saccharification and fermentation process allow to use lignocellulosic biomass as a cost-effective and high-yield strategy. However, this process requires microorganisms capable of growth at a temperature close to 50 °C, at which the activity of cellulolytic enzymes works efficiently.ResultsThe thermotolerant strain GT48 was generated by adaptive laboratory evolution in batch and chemostat cultures under temperature increments until 48 °C. The strain GT48 was able to grow and ferment glucose to d-lactate at 47 °C. It was found that a pH of 6.3 conciliated with GT48 growth and cellulase activity of a commercial cocktail. Hence, this pH was used for the SSF of a diluted acid-pretreated corn stover (DAPCS) at a solid load of 15% (w/w), 15 FPU/g-DAPCS, and 47 °C. Under such conditions, the strain GT48 exhibited remarkable performance, producing d-lactate at a level of 1.41, 1.42, and 1.48-fold higher in titer, productivity, and yield, respectively, compared to parental strain at 45 °C.ConclusionsIn general, our results show for the first time that a thermal-adapted strain of E. coli is capable of being used in the simultaneous saccharification and fermentation process without pre-saccharification stage at high temperatures.

Optimized psilocybin production in tryptophan catabolism-repressed fungi.

The high therapeutic potential of psilocybin, a prodrug of the psychotropic psilocin, holds great promise for the treatment of mental disorders such as therapy-refractory depression, alcohol use disorder and anorexia nervosa. Psilocybin has been designated a 'Breakthrough Therapy' by the US Food and Drug Administration, and therefore a sustainable production process must be established to meet future market demands. Here, we present the development of an invivo psilocybin production chassis based on repression of l-tryptophan catabolism. We demonstrate the proof of principle in Saccharomyces cerevisiae expressing the psilocybin biosynthetic genes. Deletion of the two aminotransferase genes ARO8/9 and the indoleamine 2,3-dioxygenase gene BNA2 yielded a fivefold increase of psilocybin titre. We transferred this knowledge to the filamentous fungus Aspergillus nidulans and identified functional ARO8/9 orthologs involved in fungal l-tryptophan catabolism by genome mining and cross-complementation. The double deletion mutant of A. nidulans resulted in a 10-fold increased psilocybin production. Process optimization based on respiratory activity measurements led to a final psilocybin titre of 267 mg/L in batch cultures with a space-time-yield of 3.7 mg/L/h. These results demonstrate the suitability of our engineered A. nidulans to serve as a production strain for psilocybin and other tryptamine-derived pharmaceuticals.

Review and Prospects of Xanthan Application in Water Contaminants Removal

This review explores the novel perspectives and application of xanthan in the removal of emerging water contaminants. Xanthan is a nontoxic, biocompatible, and biodegradable biopolymer of microbial origin. Industrial production of xanthan is usually conducted by aerobic submerged batch cultivation of the bacterium Xanthomonas campestris ATCC 13951 on the medium containing glucose or sucrose under optimal conditions, and findings of researchers worldwide indicate that xanthan can be successfully biosynthesized on media containing different waste streams, using various Xanthomonas strains. Common application of xanthan is in the food industry as a stabilizer, thickener, and emulsifier because of its high viscosity at lower concentrations and excellent solubility in hot and cold water. The application of xanthan is not only limited to the food and other branches of industry, but also to medicine, biomedical engineering, agriculture, and wastewater treatment. Recent studies have confirmed the excellent photocatalytic activity and emulsifying capacity of xanthan biosynthesized on waste-based media, which offers promising potential for its application in the decontamination of environment. Moreover, the xanthan-based hydrogel has great selectivity for the cationic dye and on the other side, chemically modified xanthan has a great potential as an adsorbent for the removal of metal ions.

Recent Trends in the Production and Recovery of Bioplastics Using Polyhydroxyalkanoates Copolymers

Polyhydroxyalkanoates (PHAs) are polyesters synthesized as a carbon and energy reserve material by a wide number of bacteria. These polymers are characterized by their thermoplastic properties similar to those of plastics derived from the petrochemical industry, such as polyethylene and polypropylene. PHAs are widely used in the medical field and have the potential to be used in other applications due to their biocompatibility and biodegradability. Among PHAs, P(3HB-co-3HV) copolymers are thermo-elastomeric polyesters that are typically soft and flexible with low to no crystallinity, which can expand the range of applications of these bioplastics. Several bacterial species, such as Cupriavidus necator, Azotobacter vinelandii, Halomonas sp. and Bacillus megaterium, have been successfully used for P(3HB-co-3HV) production, both in batch and fed-batch cultures using different low-cost substrates, such as vegetable and fruit waste. Nevertheless, in recent years, several fermentation strategies using other microbial models, such as methanotrophic bacterial strains as well as halophilic bacteria, have been developed in order to improve PHA production in cultivation conditions that are easily implemented on a large scale. This review aims to summarize the recent trends in the production and recovery of PHA copolymers by fermentation, including different cultivation modalities, low-cost raw materials, as well as downstream strategies that have recently been developed with the purpose of producing copolymers, such as P(3HB-co-3HV), with suitable mechanical properties for applications in the biomedical field.

Soft-sensor model development for CHO growth/production, intracellular metabolite, and glycan predictions.

Efficaciously assessing product quality remains time- and resource-intensive. Online Process Analytical Technologies (PATs), encompassing real-time monitoring tools and soft-sensor models, are indispensable for understanding process effects and real-time product quality. This research study evaluated three modeling approaches for predicting CHO cell growth and production, metabolites (extracellular, nucleotide sugar donors (NSD) and glycan profiles): Mechanistic based on first principle Michaelis-Menten kinetics (MMK), data-driven orthogonal partial least square (OPLS) and neural network machine learning (NN). Our experimental design involved galactose-fed batch cultures. MMK excelled in predicting growth and production, demonstrating its reliability in these aspects and reducing the data burden by requiring fewer inputs. However, it was less precise in simulating glycan profiles and intracellular metabolite trends. In contrast, NN and OPLS performed better for predicting precise glycan compositions but displayed shortcomings in accurately predicting growth and production. We utilized time in the training set to address NN and OPLS extrapolation challenges. OPLS and NN models demanded more extensive inputs with similar intracellular metabolite trend prediction. However, there was a significant reduction in time required to develop these two models. The guidance presented here can provide valuable insight into rapid development and application of soft-sensor models with PATs for ipurposes. Therefore, we examined three model typesmproving real-time product CHO therapeutic product quality. Coupled with emerging -omics technologies, NN and OPLS will benefit from massive data availability, and we foresee more robust prediction models that can be advantageous to kinetic or partial-kinetic (hybrid) models.

Biochemical and microbial characterization of a forest litter-based bio-fertilizer produced in batch culture by fermentation under different initial oxygen concentrations.

This work focused on the physico-chemical, biochemical and microbiological characterization of a new organic fertilizer based on fermented forest litter (FFL) mixed with agro-industrial by-products, on the culture realized in airtight glass bottle. Under strict anaerobiosis (0% initial oxygen concentration (IOC)), after a 16-day batch culture, the bottle-headspace analysis showed that the specific CO2 production rate was low (0.014 mL/h.g dry matter) compared to those reached under aerobic conditions (e.g. 0.464 mL/h.g dm at 21% IOC). Moreover, the culture displayed a slight fermented fruity odour, mainly due to ethanol and ethyl acetate detected in the headspace (335 µL and 58.6 µL accumulated, respectively). The FFL organic matter degradation followed by infrared spectroscopy and catabolic potential and diversity characterized by BIOLOG® EcoPlates were poor and pH dropped to 4.54. The microbiome's metabolism was oriented toward lactic fermentation with medium acidification, enrichment in lactic acid bacteria (LAB), depletion in fungi and absence of pathogens. By increasing IOC from 0 to 21%, the respirometric activity, and the catabolic potential and diversity increased. However, some enterobacteria were detected above 5% IOC. Ethanol and ethyl acetate decreased strongly with IOC, and aromatics and proteins contained in the solid matrix remained in the culture. This study showed the importance of oxygen on the final product. A 2% IOC was found to ensure an optimal balance between LAB development, preservation of functional catabolic diversity and bio-product free of microbial pathogens.

Clavulanic Acid Overproduction: A Review of Environmental Conditions, Metabolic Fluxes, and Strain Engineering in Streptomyces clavuligerus

Clavulanic acid is a potent β-lactamase inhibitor produced by Streptomyces clavuligerus, widely used in combination with β-lactam antibiotics to combat antimicrobial resistance. This systematic review analyzes the most successful methodologies for clavulanic acid overproduction, focusing on the highest yields reported in bench-scale and bioreactor-scale fermentations. Studies have demonstrated that glycerol is the preferred carbon source for clavulanic acid production over other sources like starch and dextrins. The optimization of feeding strategies, especially in fed-batch operations, has improved glycerol utilization and extended the clavulanic acid production phase. Organic nitrogen sources, particularly soybean protein isolates and amino acid supplements such as L-arginine, L-threonine, and L-glutamate, have been proven effective at increasing CA yields both in batch and fed-batch cultures, especially when balanced with appropriate carbon sources. Strain engineering approaches, including mutagenesis and targeted genetic modifications, have allowed for the obtainment of overproducer S. clavuligerus strains. Specifically, engineering efforts that overexpress key regulatory genes such as ccaR and claR, or that disrupt competing pathways, redirect the metabolic flux towards CA biosynthesis, leading to high clavulanic acid titers. The fed-batch operation at the bioreactor scale emerges as the most feasible alternative for prolonged clavulanic acid production with both wild-type and mutant strains, allowing for the attainment of high titers during cultivations.

Characterization and Proteomic Analysis of Geobacter sulfurreducens PCA under Long-Term Electron-Donor Starvation

The natural environment of Geobacter sulfurreducens is oligotrophic and described as limiting in both electron donors and terminal electron acceptors (TEA). In previous studies we examined the effects of long-term TEA (fumarate) limitation, and in this study we examine long-term batch cultures under limiting electron donor. The microorganism survived under long-term electron donor (acetate) starvation, maintaining a stable population of ∼1–2 × 108 cells mL−1 for >650 days. Proteins that varied in abundance with a high level of statistical significance (p < 0.05) for stages between mid-log to survival phase (acetate starved) were identified using iTRAQ based mass spectroscopy. The most highly represented proteins that significantly increased in level in the survival phase cells are generally membrane-associated and are involved in energy metabolism and protein fate. These results document that changes in the outer and cytoplasmic membranes may help G. sulfurreducens survive during starvation through detection and transport of nutrients into the cell. A sizeable portion of the identified proteins with unknown or hypothetical function further suggest that much of the biological process involved in survival have yet to be fully understood. Geobacter sulfurreducens was also able to survive under long-term TEA-starvation conditions with ferric citrate as TEA and maintained a stable population of 1.5–3 × 107 cells mL−1 for >650 days. We also found that survival phase cells from fumarate-limiting conditions were able to quickly resuscitate and reduce metal such as ferric iron as compared to the mid-log phase cells.

Effects of Active Dry Yeast Supplementation in In Vitro and In Vivo Nutrient Digestibility, Rumen Fermentation, and Bacterial Community.

This study assessed the impact of active dry yeast (ADY) on nutrient digestibility and rumen fermentation, using both in vitro and in vivo experiments with lambs. In vitro, ADYs were incubated with rumen fluid and a substrate mixture to assess gas production, pH, volatile fatty acid (VFA) profiles, and lactate concentration. In vivo, Hu lambs were randomly assigned to five dietary treatments: a control group and four groups receiving one of two dosages of either Vistacell or Procreatin7. Growth performance, nutrient digestibility, rumen fermentation parameters, and bacterial community composition were measured. Pro enhanced the propionate molar proportion while it decreased the n-butyrate molar proportion. Vis reduced the lactate concentration in vitro. In the in vivo experiment, Vis increased the propionate molar proportion and the Succinivibrionaceae_UCG-001 abundance while it decreased the n-butyrate molar proportion and the Lachnospiraceae_ND3007 abundance. Additionally, Vis showed a greater impact on improving the NDF digestibility and total VFA concentration in vivo compared to Pro. Overall, the effects of ADYs on rumen fermentation were found to vary depending on the specific ADY used, with Vis being the most suitable for lamb growth. It was observed that Vis promoted propionate fermentation and Succinivibrionaceae_UCG-001 abundance at the expense of reduced n-butyrate fermentation and Lachnospiraceae_ND3007 abundance. Importantly, differences were noted between the outcomes of the in vitro and in vivo experiments concerning the effects of ADYs on rumen fermentation, highlighting the need for caution when generalizing batch culture results to the in vivo effects of ADYs.

Rapid Screening of Methane-Reducing Compounds for Deployment in Livestock Drinking Water Using In Vitro and FTIR-ATR Analyses

Several additives have been shown to reduce enteric methane emissions from ruminants when supplied in feed. However, utilising this method to deliver such methane-reducing compounds (MRCs) in extensive grazing systems is challenging. Use of livestock drinking water presents a novel method to deliver MRCs to animals in those systems. This work evaluated 13 MRCs for suitability to be deployed in this manner. Compounds were analysed for solubility and stability in aqueous solution using Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Furthermore, aqueous solutions of MRCs were subjected to variations in temperature and starting pH of water used to assess solubility and stability of the MRCs in simulated water trough conditions, also using FTIR-ATR spectroscopy. In vitro batch culture fermentations were carried out using a medium-quality tropical grass feed substrate, to simulate pastures consumed by cattle in extensive grazing systems. Measurements were made of total gas and methane production, in vitro dry matter digestibility (IVDMD), and volatile fatty acid (VFA) concentration. Of the MRCs tested, 12 were found to be soluble and stable in water using the FTIR method employed, whilst the other could not be measured. Of the 12 soluble and stable MRCs, one containing synthetic tribromomethane (Rumin8 Investigational Veterinary Product) reduced methane production by 99% (p = 0.001) when delivered aqueously in vitro, without a reduction in IVDMD (p = 0.751), with a shift towards decreased acetate and increased propionate production and decreased total VFA production (p &lt; 0.001). Other compounds investigated also appeared suitable, and the methods developed in this study could be used to guide future research in the area.

Selection of highly ethanol productive yeast

Seventy five isolates of Saccharomyces cerevisiae were identified, they were isolated from different local sources which included decayed fruits and vegetables, vinegar, fermented pasta, baker yeast and an alcohol factory. Identification of isolates was carried out by cultural microscopical and biochemical tests. Ethanol sensitivity of the isolates showed that the minimal inhibitory concentration of the isolate (Sy18) was 16% and Lethal concentration was 17%. The isolate (Sy18) was most efficient as ethanol producer 9.36% (v/w). The ideal conditions to produce ethanol from Date syrup by yeast isolate, were evaluated, various temperatures, pH, Brix, incubation period and different levels of (NH4)2HP04. Maximum ethanol produced was 10.32% (v/v). Experimental production of ethanol using continuous methodology with immobilized cells of Saccharomyces cerevisiae showed that this method is superior by producing 5.83 g/L/h in comparison with 1.95 g/l/h produced by batch culture method

Improved hydrogen production in immobilized Chlamydomonas reinhardtii cells with inhibited inter-photosystem electron transfer

The production of molecular hydrogen (H2) by microalgae holds great promise, and immobilization techniques offer potential for further advancement in this field. The current study focuses on investigating the positive impact of immobilization on maintaining the stability and activity of photosystem II (PSII) over incubation time, with the aim of enhancing H2 production potential in green microalgae Chlamydomonas reinhardtii. For this purpose, immobilized cells within alginate beads were treated with small concentrations of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB) inhibitor to induce the partial inhibition of inter-photosystem electron transport, recently reported as a novel approach for sustaining microalgal H2 production. A comparative analysis of fluorescence decay kinetic changes and EPR spectroscopy of the cell beads revealed the superior capacity of immobilization for sustaining PSII stability and activity in batch culture over time. Treatment of the cell beads with 3.5 μM DBMIB led to sustained H2 production yielding over 200 μmol H2/mg Chl within 3 weeks, with an average H2 production rate of approximately 10 μmol/mg Chl per day, both of which were roughly twice as high as those observed in free cells treated with DBMIB. Our findings underscore the significance of integrating immobilization with a proven and effective method for H2 production, thereby enhancing its sustainability and productivity.

A comparative study on biodegradation of low density polyethylene bags by a Rhizopus arrhizus SLNEA1 strain in batch and continuous cultures.

Biodegradation poses a challenge for environmentalists and scientific community, offering a potential solution to the plastic waste problem. This study aims to investigate the biological degradation of low-density polyethylene (LDPE) bags by a fungus in both batch and continuous cultures, with the goal of identifying an eco-friendly and cost-effective waste management strategy. The fungal strain Rhizopus arrhizus SLNEA1, isolated from a landfill located in northeastern Algeria, was tested for its capability to degrade LDPE films and utilize them as a sole carbon source in batch (α-LDPE) and continuous (γ-LDPE) cultures. The results indicated a higher rate of weight loss for γ-LDPE (29.74%) compared to α-LDPE (23.77%). The biodegradation effect was examined using scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) to evaluate morphological and chemical changes in LDPE samples, highlighting alterations of LDPE films through cracks, veins and holes under SEM and chemical transformation and appearance of new functional groups in the FTIR data. Rhizopus arrhizus SLNEA1 demonstrated the ability to break down and utilize LDPE films as a carbon source. This isolate shows promise for LDPE biodegradation applications, which may be leveraged for the development of future plastic degradation systems involving fungi.

The Combined Effect of Four Nutraceutical-Based Feed Additives on the Rumen Microbiome, Methane Gas Emission, Volatile Fatty Acids, and Dry Matter Disappearance Using an In Vitro Batch Culture Technique

This study aimed to investigate the effect of an essential oil/fumaric combination, mannan-oligosaccharide, galactooligosaccharide, and a mannan-oligosaccharide/galactooligosaccharide combination on the dry matter disappearance (DMD), gas production, greenhouse gasses, volatile fatty acid, and microbial community of a total mixed ration using a 24 h in vitro batch culture technique. The study design was a completely randomized design with four treatments as follows: a control treatment without any additives, the control treatment supplemented with galactooligosaccharide at 3% (Gos treatment), a galactooligosaccharide and mannan-oligosaccharide mixture at 1:1 at 3% (Gosmos treatment), or an essential oil blend (200 μL/g feed) and fumaric acid at 3% combination (Eofumaric treatment). The Gosmos treatment had the highest (p &lt; 0.05) DMD (63.8%) and the numerical lowest acetate–propionate ratio (p = 0.207), which was 36.9% higher compared to the control. The lowest Shannon index, Simpson’s index, and all the diversity indices were recorded for the Eofumaric treatment, while the other treatments had similar Shannon index, Simpson’s index, and diversity index. The Z-score differential abundance between the Eofumaric and the control indicated that the inclusion of the Eofumaric treatment differentially increased the abundance of Patescibacteria, Synergistota, Chloroflexi, Actinobacteriota, Firmicutes, and Euryarchaeota while Verrucomicrobiota, WPS-2, Fibrobacterota, and Spirochaetota were decreased. The Random Forest Classification showed that the lower relative abundance of Fibrobacterota, Spirochaetota, and Elusimicrobiota and the higher relative abundance of Firmicutes and Chloroflexi were most impactful in explaining the microbial community data. Overall, the essential oil blend showed great potential as a methane gas mitigation strategy by modifying rumen fermentation through changes in the microbial community dynamics.

Exploring the nutraceutical potential of high-altitude freshwater diatom Nitzschia sp. in batch culture

Exploring the nutraceutical potential of high-altitude freshwater diatom Nitzschia sp. in batch culture

Assessment of in situ product recovery techniques to enhance 2-phenylethanol production by Acinetobacter soli ANG344B

The 2-phenylethanol (2-PE) production process by the newly isolated Acinetobacter soli ANG344B is limited by product toxicity. To overcome this limitation and enhance 2-PE production process, various alternatives based in in situ product removal (ISPR) approaches were evaluated. The approaches selected for assessment were gas stripping using the air supplied to the bioreactor, liquid-liquid extraction and adsorption. Adsorption was found to be the most promising approach to increase 2-PE production. Amberlite XAD 4 was chosen from the different adsorbents tested since it has high affinity for 2-PE, being able to adsorb 205.8 ± 8.1 mg2-PE/gdry resin. In a batch cultivation process, in presence of 3 % (dry w/v) of Amberlite XAD 4, A. soli ANG344B was able to produce 6.99 ± 0.06 g/L of 2-PE with a volumetric productivity of 0.17 ± 0.00 g/L.h, which represents an improvement of 3.3-fold. To the best of our knowledge, this is the highest 2-PE production reported for a wild-type bacteria. These findings highlight the potential of Acinetobacter soli ANG344B as 2-PE producer, contributing to the development of natural 2-PE production process.

Untargeted metabolomics profiling of tropical marine microalgae in batch culture system with different mobile phase using Liquid Chromatography-Orbitrap High-resolution Mass Spectrometry combined with chemometrics

Microalgae have recently been identified as a valuable source of natural bioactive compounds, with potential applications suggested in areas such as food, animal feed, energy production (biofuels), fine chemicals, and pharmaceuticals. However, their chemical diversity remains largely unexplored and it is necessary to determine their potency for further application. This study will explore the diversity of chemical compound from six tropical marine microalgae with untargeted comparative metabolomics approach using a Liquid Chromatography-Orbitrap High Resolution Mass Spectrometry with different mobile phases. Six microalgae species were isolated from Jakarta Bay, Indonesia. Species identification was carried out using morphological and molecular identification. The isolates Chlorella vulgaris InaCC M205 (C5), Chlorella sp. 12 (C12), Tetraselmis subcordiformis InaCC M206 (T2), Tetraselmis sp. 5 (T5), Nannochloropsis oceanica InaCC 207 (N4), and Porphyridium purpureum (P) were then cultivated using f/2 media in 1 L glass photobioreactors, irradiated with daylight lamps (4000 lux) under a 12 h/12 h photoperiod at 25 0C for until cultures reached the stationary phase. Biomass harvesting and measurements were carried out at the end of the culture period. The freeze-dry biomass then was analyzed using liquid chromatography-high resolution mass spectrometry. The results showed that biomass production on day 12 was not significantly different. Biomass production ranged from 0.8 to 1 g/L, with the highest production obtained from the C5 strain and the lowest from the C12 strain. Chromatography analysis revealed that untargeted metabolomics profiling of microalgae, using water-acetonitrile as mobile phase, identified potential compound markers such as N-Methyl-2-pyrrolidone, l-(+)-Cysteine, TBHQ and L-Phenylalanine, which can differentiate between species. Compound such as Cyromazine, Arachidic acid and 13(S)-HOTrE were the potential compound markers when using Water-Methanol as mobile phase. Our research indicates that the metabolomic profile of microalgae can be used to differentiate species depending on the choice of mobile phase.

Growth of Lactiplantibacillus plantarum BG112 in Batch and Continuous Culture with Camellia sinensis as Prebiotic

This work aimed to study the effect of Camellia sinensis extract (CSExt) as a particular growth promoter of Lactiplantibacillus plantarum (LP) in batch and continuous production processes. Growth conditions were 1% (v/v) inoculum, pHC = 6.5, 1% of dissolved oxygen (D.O.), 37 °C, and 150 rpm in a 0.2 L bioreactor using a commercial MRS broth (de Man, Rogosa, and Sharpe) and 1% (v/v) or 10% (v/v) CSExt according to the experimental design. In batch experiments, the maximum specific growth rate and the affinity constant increased with the increase in CSExt. In continuous culture, biomass production increased significantly with the addition of 1% (w/v) CSExt at 0.15 (1/h). Kinetic parameters adjusted were similar to those reported in the literature. Substrate affinity and the specific growth rate increased significantly in the presence of CSExt in batch and continuous cultures. Based on the results, prebiotics from plant extracts may function as growth promoters in specific physiological stages. This is the first report showing the change in kinetic parameters of a probiotic strain growing in crude plant extracts.

Mathematical modeling of an isothermal tubular bioreactor coupled with batch culture for ethanol production: a one-dimensional approach

Mathematical modeling of an isothermal tubular bioreactor coupled with batch culture for ethanol production: a one-dimensional approach