Nutrient optimization in bioleaching: are we overdosing?

The general trend in biomining (i.e., bioleaching and biooxidation) is the use of media with high concentrations of the nutrients (nitrogen as ammonium, phosphorous as phosphate, and K), which are considered to be essential for microbial growth. The depletion of any of the nutrients would affect negatively the bioleaching (and biooxidation) capacity of the microorganisms, so the formulation of the different media ensures that there is a surplus of nutrients. However, some of these nutrients (e.g., phosphate, K) may be already present in the ore and are made available to the microorganisms when the ore is exposed to the low-pH media used during bioleaching. The effect of phosphate addition (109 mg/L) and depletion on the bioleaching of low-grade sulfidic ore alongside the determination of ammonium (i.e., 25 mg/L, 50 mg/L, 109 mg/L, 409 mg/L, and 874 g/L) requirements were studied. The results of the experiments presented showed that the addition of phosphate did not have any effect on the bioleaching of the low-grade sulfidic ore while the addition of ammonium was necessary to obtain higher redox potentials (>650 mV vs. Ag/AgCl) and higher metal (Co, Cu, Ni, and Zn) dissolutions. Temperature was the factor that shaped the microbial communities, at 30°C, the microbial community at the end of all the experiments was dominated by Acidithiobacillus sp. as well as at 42°C, except when nutrients were not added and Sulfobacillus sp. was the dominant microorganism. At 55°C, DNA recovery was unsuccessful, and at 60°C, the microbial communities were dominated by Sulfolobus sp. In conclusion, the amount of nutrients in bioleaching could be reduced significantly to achieve the redox potentials and metal dissolution desired in bioleaching without affecting the microbial communities and bioleaching efficiencies.

An update on microfluidic multi-organ-on-a-chip systems for reproducing drug pharmacokinetics: the current state-of-the-art.

INTRODUCTION: Advances in the accessibility of manufacturing technologies and iPSC-based modeling have accelerated the overall progress of organs-on-a-chip. Notably, the progress in multi-organ systems is not progressing with equal speed, indicating that there are still major technological barriers to overcome that may include biological relevance, technological usability as well as overall accessibility. AREAS COVERED: We here review the progress in the field of multi-tissue- and body-on-a-chip pre and post- SARS-CoV-2 pandemic and review five selected studies with increasingly complex multi-organ chips aiming at pharmacological studies. EXPERT OPINION: We discuss future and necessary advances in the field of multi-organ chips including how to overcome challenges regarding cell diversity, improved culture conditions, model translatability as well as sensor integrations to enable microsystems to cover organ-organ interactions in not only toxicokinetic but more importantly pharmacodynamic and -kinetic studies.

Cultivated meat manufacturing: Technology, trends, and challenges.

The growing world population, public awareness of animal welfare, environmental impacts and changes in meat consumption leads to the search for novel approaches to food production. Novel foods include products with a new or specifically modified molecular structure, foods made from microorganisms, fungi, algae or insects, as well as from animal cell or tissue cultures. The latter approach is known by various names: "clean meat", "in vitro meat" and "cell-cultured" or "(cell-)cultivated meat". Here, cells isolated from agronomically important species are expanded ex vivo to produce cell biomass used in unstructured meat or to grow and differentiate cells on scaffolds to produce structured meat analogues. Despite the fast-growing field and high financial interest from investors and governments, cultivated meat production still faces challenges ranging from cell source choice, affordable expansion, use of cruelty-free and food-grade media, regulatory issues and consumer acceptance. This overview discusses the above challenges and possible solutions and strategies in the production of cultivated meat. The review integrates multifaceted historical, social, and technological insights of the field, and provides both an engaging comprehensive introduction for general interested and a robust perspective for experts.

Comprehensive Exploration of the Growth and Lipid Synthesis Phases of T. oleaginosus Cultures Implementing Design of Experiments and Response Surface Methodology.

Trichosporon oleaginosus is an unconventional oleaginous yeast distinguished by its remarkable capacity to accumulate lipids in excess of 70% of its dry weight, particularly when cultivated in nitrogen-restricted conditions with ample carbon sources. A pivotal question that arises pertains to the nutrient dynamics in the culture medium, which give rise to both the excessive lipid content and corresponding lipid concentration. While previous research has predominantly focused on evaluating the impact of the initial carbon-to-nitrogen (C/N) ratio on lipid production, the precise critical thresholds of glucose and ammonium sulfate ((NH4)2SO4) at which growth and intracellular lipid production are either stimulated or impeded remain inadequately defined. This study employs an experimental design and response surface methodology to investigate the complex mechanism of lipid accumulation and its interaction with cellular growth. Application of the aforementioned methodologies resulted in the production of 10.6 g/L of microbial oil in batch cultures under conditions that correspond to a C/N ratio of 76. However, the primary objective is to generate knowledge to facilitate the development of efficient fed-batch cultivation strategies that optimize lipid production exclusively employing inorganic nitrogen sources by finely adjusting carbon and nitrogen levels. The intricate interaction between these levels is comprehensively addressed in the present study, while it is additionally revealed that as glucose levels rise within a non-inhibitory range, lipid-free biomass production decreases while lipid accumulation simultaneously increases. These findings set the stage for further exploration and the potential development of two-stage cultivation approaches, aiming to fully decouple growth and lipid production. This advancement holds the promise of bringing microbial oil production closer to commercial viability.

Influence of Media Composition on the Level of Bovine Satellite Cell Proliferation.

It is predicted that already in 2040, 35% of requirements for meat will be provided by in vitro production. Recreating the course of myogenesis in vitro, and thus resembling a structure of muscle tissue, is the basis for research focusing on obtaining cultured meat and requires providing relevant factors supporting the proliferation of satellite cells-being precursors of skeletal muscles. The present work aimed to develop the composition of the medium that would most effectively stimulate the proliferation of bovine satellite cells (BSCs). The modeling and optimization methods included the measurements of the synergistic, co-stimulatory effect of three medium components: the amount of glucose, the type of serum (bovine or horse), and the amount of mitogenic factor-bFGF. Additionally, the qPCR analyses determined the expression of genes involved in myogenesis, such as Pax7 and Myogenic Regulatory Factors, depending on the level of the tested factor. The results showed significant positive effects of serum type (bovine serum) and mitogenic factor (addition of 10 ng/mL bFGF) on the proliferation rate. In turn, qPCR analysis displayed no significant differences in the relative expression level of Pax7 genes and MRF factors for both factors. However, a statistically higher Pax7 and Myf5 gene expression level was revealed when a low glucose medium was used (p < 0.05). In conclusion, the components of the medium, such as bovine serum and the addition of a mitogenic factor at the level of 10 ng/mL, ensure a higher proliferation rate of BSCs and lower glucose content ensured the expression of crucial genes in the self-renewal of the satellite cell population.

Metabolic Priming as a Tool in Redox and Mitochondrial Theragnostics.

Theragnostics is a promising approach that integrates diagnostics and therapeutics into a single personalized strategy. To conduct effective theragnostic studies, it is essential to create an in vitro environment that accurately reflects the in vivo conditions. In this review, we discuss the importance of redox homeostasis and mitochondrial function in the context of personalized theragnostic approaches. Cells have several ways to respond to metabolic stress, including changes in protein localization, density, and degradation, which can promote cell survival. However, disruption of redox homeostasis can lead to oxidative stress and cellular damage, which are implicated in various diseases. Models of oxidative stress and mitochondrial dysfunction should be developed in metabolically conditioned cells to explore the underlying mechanisms of diseases and develop new therapies. By choosing an appropriate cellular model, adjusting cell culture conditions and validating the cellular model, it is possible to identify the most promising therapeutic options and tailor treatments to individual patients. Overall, we highlight the importance of precise and individualized approaches in theragnostics and the need to develop accurate in vitro models that reflect the in vivo conditions.

Influence of bacterial and alveolar cell co-culture on microbial VOC production using HS-GC/MS.

Volatile organic compounds (VOCs) found in exhaled breath continue to garner interest as an alternative diagnostic tool in pulmonary infections yet, their clinical integration remains a challenge with difficulties in translating identified biomarkers. Alterations in bacterial metabolism secondary to host nutritional availability may explain this but is often inadequately modelled in vitro. The influence of more clinically relevant nutrients on VOC production for two common respiratory pathogens was investigated. VOCs from Staphylococcus aureus (S.aureus) and Pseudomonas aeruginosa (P.aeruginosa) cultured with and without human alveolar A549 epithelial cells were analyzed using headspace extraction coupled with gas chromatography-mass spectrometry. Untargeted and targeted analyses were performed, volatile molecules identified from published data, and the differences in VOC production evaluated. Principal component analysis (PCA) could differentiate alveolar cells from either S. aureus or P. aeruginosa when cultured in isolation based on PC1 (p = 0.0017 and 0.0498, respectively). However, this separation was lost for S. aureus (p = 0.31) but not for P. aeruginosa (p = 0.028) when they were cultured with alveolar cells. S. aureus cultured with alveolar cells led to higher concentrations of two candidate biomarkers, 3-methyl-1-butanol (p = 0.001) and 3-methylbutanal (p = 0.002) when compared to S. aureus, alone. P. aeruginosa metabolism resulted in less generation of pathogen-associated VOCs when co-cultured with alveolar cells compared to culturing in isolation. VOC biomarkers previously considered indicative of bacterial presence are influenced by the local nutritional environment and this should be considered when evaluating their biochemical origin.

Optimization of the In Vitro Proliferation of an Ancient Pear Tree Cultivar ('Decana d'inverno') through the Use of Neem Oil.

In vitro culture, ensuring rapid multiplication and production of plant material under aseptic conditions, represents an excellent tool for ex-situ conservation of tree species biodiversity and can be used for the conservation, among others, of endangered and rare crops. Among the Pyrus communis L. cultivars that have been abandoned over the years due to changed cultivation requirements, but which are still used today in breeding programs, there is the 'Decana d'inverno'. Pear is generally considered a recalcitrant species for in vitro propagation due to weak multiplication rate, hyperhydricity, and susceptibility to phenolic oxidation. Therefore, the use of natural substances like neem oil (although little explored) represents one of the options to improve the in vitro plant's tissue culture. In this context, the aim of the present work was to evaluate the effect of adding neem oil (0.1 and 0.5 m L L-1) to the growth substrate in order to optimise the in vitro culture of the ancient pear tree cultivar 'Decana d'inverno'. The neem oil addition resulted in an increase in the number of shoots produced especially at both concentrations used. On the contrary, an increase in length of proliferated shoots was observed only with the addition of 0.1 mL L-1. The neem oil addition did not affect the explants viability, fresh and dry weights. Therefore, the present study demonstrated for the first time the possibility of using neem oil to optimise the in vitro culture of an ancient pear tree cultivar.

Bioremediation by oil degrading marine bacteria: An overview of supplements and pathways in key processes.

Oil spillage is one of the most common pollutants which brings greater economic loss and damage to the environment. The intensity and amount of the damage may vary depending on factors such as the type of oil, the location of the spill, and the climatic parameters in the area. As for any pollution management, the guidelines are Reduce, Re-use, Recover and Disposal. Amongst the other remediation processes, Bioremediation is amongst the most significant environmentally friendly and cost-effective approaches for marine biological restoration because it allows complex petroleum hydrocarbons in spilt oil to decompose completely into harmless compounds. Mainly, the necessity and essence of bioremediation were talked about. This review discussed the bacteria identified which are capable of degrading various oil related pollutants and their components. Also, it covered the various media components used for screening and growing the oil degrading bacteria and the pathways that are associated with oil degradation. This article also reviewed the recent research carried out related to the oil degrading bacteria.

Honing the Double-Edged Sword: Improving Human iPSC-Microglia Models.

Human induced Pluripotent Stem Cell (hiPSC) models are a valuable new tool for research into neurodegenerative diseases. Neuroinflammation is now recognized as a key process in neurodegenerative disease and aging, and microglia are central players in this. A plethora of hiPSC-derived microglial models have been published recently to explore neuroinflammation, ranging from monoculture through to xenotransplantation. However, combining physiological relevance, reproducibility, and scalability into one model is still a challenge. We examine key features of the in vitro microglial environment, especially media composition, extracellular matrix, and co-culture, to identify areas for improvement in current hiPSC-microglia models.

Impact of Cultivation Condition and Media Content onChlorella vulgaris Composition.

Microalgae are a source material in food, pharmacy, and cosmetics industries for producing various products including high-protein nutritional supplements, synthetic pharmaceuticals, and natural colors. A promising algal source for such productions is Chlorella vulgaris which contains a considerable protein content. Similar to other microalgae, its desirability is minimal nutrient requirements since they are unicellular, photosynthetic, and fast-growing microorganisms. Another propitious option to be produced by C. vulgaris is biodiesel, since it is rich in oil too. Besides, algal well thriving in presence of increased amount of carbon dioxide makes them a practicable alternative biofuel resource without some problems of the traditional ones. At the same time, C. vulgaris is also a promising source for nutraceuticals such as amino acids, vitamins, and antioxidants. This review aims to discuss the conditions need to be observed for achieving a favorable growth efficiency of the C. vulgaris, as well as targeted productions such as biomass, antioxidant, and biofuel. Additionally, different approaches to induce any specific production are also considered comprehensively.

The impact of media composition on production of flavonoids in agitated shoot cultures of the three Hypericum perforatum L. cultivars 'Elixir,' 'Helos,' and 'Topas'.

The aims of the study were to evaluate the effect of media composition on the growth potential and morphology of the in vitro cultured biomass of three cultivars of Hypericum perforatum, and on the production of flavonoids. Agitated shoot cultures were maintained in parallel on Linsmaier and Skoog (LS) and Murashige and Skoog (MS) media supplemented with 0.1-3.0 mg L-1 of α-naphthaleneacetic acid and 6-benzylaminopurine. Methanolic extracts from the biomass collected after 3-wk growth cycles were analyzed quantitatively, for 21 flavonoids using high performance liquid chromatography. Three aglycones (kaempferol, luteolin, and quercetin) and three glycosides of quercetin (hyperoside, quercitrin, and rutoside) were detected in all of the extracts. The total amounts of the estimated compounds increased from 1.18- to 21.66-fold on LS media variants and from 1.52- to 17.34-fold on MS media variants. The main metabolite was quercetin (max. 210.55 mg 100 g-1 dry weight [DW]). The maximum total amounts of all compounds in the biomass of 'Elixir,' 'Helos,' and 'Topas' were 328.53, 255.70, and 166.58 mg 100 g-1 DW, respectively. The shoots of all cultivars cultivated on the LS and MS media containing low levels of plant growth regulators (0.1 mg L-1) accumulated high amounts of flavonoids. The highest amounts were accumulated in shoots of cultivar 'Elixir' grown on MS medium. This is the first comparison of flavonoid production in three cultivars of H. perforatum ('Elixir,' 'Helos,' and 'Topas') cultured in vitro, and the first report of flavonoid production in cultivars 'Elixir' and 'Helos.'

Cytotoxic effect of proteinaceous postbiotic metabolites produced by Lactobacillus plantarum I-UL4 cultivated in different media composition on MCF-7 breast cancer cell

Aims: Lactobacillus sp. has capability of producing an array of bioactive metabolites that exhibit probiotic effects. Therefore, the objective of this study was to determine the cytotoxicity effect of proteinaceous postbiotic metabolites (PPM) produced by Lactobacillus plantarum I-UL4 cultivated in different media composition on MCF-7 breast cancer cell. Methodology and results: L. plantarum I-UL4 was cultivated in yeast extract and modified de Man, Rogosa and Sharpe broth containing Tween 80 (CRMRS+T80) or without Tween-80 (CRMRS-T80). Human breast adenocarcinoma cell (MCF-7) was employed as cancer cell in this study. Cytotoxicity and antiproliferative effects of PPM were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl Tetrazolium Bromide assay and Trypan Blue Dye Exclusion assay, whereas Acridine Orange/Propidium Iodide staining was employed to determine the cytotoxicity mechanism. PPM produced in CRMRS+T80 exerted cytotoxicity in a time and dose dependent manner that was selective towards MCF-7 cancer cell. Profound cytotoxicity with the lowest IC50 concentration of 10.83 µg was detected at 72 h of incubation, whereas the most potent antiproliferative effect revealed by the lowest viable cell population was observed at 24 h of incubation. PPM cultivated in CRMRS+T80 induced 80.87% of apoptotic MCF-7 cells at 48 h of incubation. Conclusion, significance and impact of study: PPM of L. plantarum I-UL4 cultivated in different media composition induced different levels of MCF-7 cancer cell death. The percentage of apoptotic MCF-7 cells treated with PPM cultivated in CRMRS+T80 increased significantly (p < 0.05) from 24 to 48 h of incubation. The results obtained in this study have revealed the potential of PPM produced by L. plantarum I-UL4 as human health supplement and as anticancer preventive agent. Keywords: Lactobacillus plantarum I-UL4; cytotoxic effect; proteinaceous postbiotic metabolites; media composition; breast cancer

Effects of different media composition, light intensity and photoperiod on morphology and physiology of freshwater microalgae Ankistrodesmus falcatus--a potential strain for bio-fuel production.

Media composition, light intensity and photoperiod significantly affect the algal growth and productivity and their optimization is important for the commercialization of microalgae based biofuels. In the present study, effects of different culture medium, light intensity and photoperiod were studied on growth, biomass productivity, and biochemical composition of a fresh water microalgae Ankistrodesmus falcatus in batch culture. The results revealed that A. falcatus could yield more than 35% of total lipid (containing around 65.74% neutral lipid) along with optimal growth (0.20 µ) and biomass productivity (7.9 mg/L/day) in the BG-11 medium under a light intensity of 60 µmol m(-2) s(-1) and 12:12 (Light: Dark) cycle. The highest total lipid yield of 67.2% (containing 72.68% of neutral lipid) was observed in Zarrouk's medium grown culture but with altered cell morphology and ultra-structural changes.

Deep-frying food in extra virgin olive oil: a study by (1)H nuclear magnetic resonance of the influence of food nature on the evolving composition of the frying medium.

Three series of fourteen deep-frying experiments on three foods of very different compositions were carried out using extra virgin olive oil as the original frying medium. The aim of the study was to establish how the nature of the food being fried influences the composition of the frying medium. The changes in the composition of the frying media referred to the evolution of molar percentage of the different kinds of acyl groups, as well as to the evolution of the concentration of newly formed compounds such as aldehydes, epoxystearyl groups, primary and secondary alcohols were monitored in a simultaneous way by (1)H NMR spectroscopy. Changes due to hydrolytic processes were also considered. In addition, the evolution of the Iodine Value and percentage in weight of polar compounds was also analysed. The influence of food lipids migration to the frying medium on the composition of this latter was evidenced.