Use Of Alternative Substrates Research Articles

Production of high-quality seedlings of Handroanthus spongiosus (Bignoniaceae), native to a seasonally dry tropical forest

Studies of the use of alternative substrates have enabled producing seedlings of various species with high quality and low cost. The objective of this work was to evaluate the best cultivation conditions for production of Handroanthus spongiosus seedlings. The seeds were collected from five different populations in the state of Pernambuco, Brazil, and cultivated in six substrates: soil, sand, soil + vermiculite, soil + goat manure, soil + vermiculite + goat manure, and soil + goat manure + 30% biochar. We evaluated the emergence, shoot and root length, stem base diameter, shoot and root dry mass, and Dickson quality index. The substrates with addition of organic matter favored increased shoot length, stem diameter and dry mass. The incorporation of goat manure and biochar in the substrates favored the quality of the H. spongiosus seedlings.

Alternative substrates in the cultivation of ornamental and vegetable plants

Research objective: The aim of this research was to evaluate different types of innovative substrate mixtures as an alternative to traditional growing media with peat and pumice on vegetable and ornamental plants Materials and Methods: The experiments, which began in November 2022, were conducted in the CREA-OF greenhouses in Pescia (Pt), Tuscany, Italy (43°54′N 10°41′E) on seedlings of Arbutus unedo, Photinia red robin, Fragaria vesca and Crassula sarcocaulis. The plants were placed in 14 diameter pots, 6 plants per 3 replications, for a total of 18 seedlings per experimental thesis. The test was divided into two parallel trials with different substrates. The first trial on Crassula sarcocaulis involved the following theses (irrigated and fertilised): peat 70% + pumice 30%; peat 65% + pumice 30% + biochar 5%; compost 60% + biochar 5% + insect humus 5% + pumice 30%; compost 60% + biochar 5% + earthworm humus 5% + pumice 30%. The second trial on Arbutus unedo, Photinia red robin and Fragaria vesca involved the following theses (irrigated and fertilised): peat 70% + pumice 30%; alternative soil 72% + biochar 5% + 3% humus + 20% pumice. On 18 May 2023, plant height, vegetative weight, root volume and length, number of fruits (strawberry) and number of microorganisms were determined. Results and Discussion: The experiment showed that the use of alternative substrates can effectively improve the vegetative and root growth of Crassula sarcocaulis, Fragaria vesca, Photinia red robin and Arbutus unedo. In general, in the first experiment on Crassula sarcocaulis, a significant increase in plant height was observed with the biochar-only substrate, followed by the insect and earthworm humus-based theses. All the theses were significantly better than the control with peat and pumice. In the second trial on Fragaria vesca, Photinia red robin and Arbutus unedo, the thesis with altenative soil, biochar and humus was significantly better in all plant species for plant height, vegetative and root weight and root length. All alternative substrates showed a significant increase in microbial biomass compared to the control. Several materials have been evaluated as substitutes for or combination with peat in growing media formulation. They include coir dust, pine bark, and wood fiber as well as sand, tuff, and pumice processed materials (expanded clay, perlite, and vermiculite). Besides satisfying the relevant technical requirements, these alternatives have to be readily available at reasonable prices and be readily available in sufficient quantities. In addition to meeting specific plant requirements, these materials have been used to create tailored growing media that are environmentally friendly and reduce production costs. Conclusions: The results of research on growing substrates must be translated into agricultural practice through various steps, in cooperation with horticultural companies. To ensure the best growing conditions for seedlings, nurseries should conduct a thorough analysis of the specific composts they use. As organic farming practitioners argue, greater involvement of compost producers and end-users could improve the quality of growing media by adding additional valuable characteristics and reducing the use of peat, which would allow for a more sustainable regime.

Modified Lactoperoxidase System as a Promising Anticaries Agent: In Vitro Studies on Streptococcus mutans Biofilms.

The lactoperoxidase (LPO) system shows promise in the prevention of dental caries, a common chronic disease. This system has antimicrobial properties and is part of the non-specific antimicrobial immune system. Understanding the efficacy of the LPO system in the fight against biofilms could provide information on alternative strategies for the prevention and treatment of caries. In this study, the enzymatic system was modified using four different (pseudo)halide substrates (thiocyanate, thiocyanate-iodide mixture, selenocyanate, and iodide). The study evaluated the metabolic effects of applying such modifications to Streptococcus mutans; in particular: (1) biofilm formation, (2) synthesis of insoluble polysaccharides, (3) lactate synthesis, (4) glucose and sucrose consumption, (5) intracellular NAD+ and NADH concentrations, and (6) transmembrane glucose transport efficiency (PTS activity). The results showed that the LPO-iodide system had the strongest inhibitory effect on biofilm growth and lactate synthesis (complete inhibition). This was associated with an increase in the NAD+/NADH ratio and an inhibition of glucose PTS activity. The LPO-selenocyanate system showed a moderate inhibitory effect on biofilm biomass growth and lactate synthesis. The other systems showed relatively small inhibition of lactate synthesis and glucose PTS but no effect on the growth of biofilm biomass. This study provides a basis for further research on the use of alternative substrates with the LPO system, particularly the LPO-iodide system, in the prevention and control of biofilm-related diseases.

Application of Metabolic Engineering Approaches in Enhancing Biological Hydrogen Production

Hydrogen is useful as a fuel and could be produced by a variety of means. One approach uses artificial photosynthesis where energy from sunlight powers the splitting of water into hydrogen and oxygen. But, biological methods for producing hydrogen has emerged strongly over the past decades. In particular, specific microorganisms could use different substrates to produce hydrogen at differing yields. Such fundamental discoveries with industrial applications thus motivated the use of metabolic engineering approaches and methodologies in enhancing biological hydrogen production through a series of enzyme over-expression, pathway debottlenecking, and gene deletion. However, such approaches heavily rely on the selection of an appropriate microbial chassis for biohydrogen production. With the proper strain in hand, use of alternative substrates may engender greater hydrogen productivities. But learning from the bioprocessing field, co-culture of two compatible microorganisms have been sought after for improving biohydrogen production. In addition, thermophilic microbes may also be useful candidates for exploiting hydrogen production from composting. Future outlook in the field looks into filling our gaps in understanding of the metabolic network that feeds into hydrogen production in different organisms. But, more importantly, problems such as reduced growth rate in engineered microbes point to fundamental issues with using genetically engineered microorganisms for improved biohydrogen production, to which clever bioprocess engineering may yield solutions.

Germination test in carioca bean seeds chemically treated with the use of alternative substrates

The use of quality seeds is a key element for the success of carioca bean (Phaseolus vulgaris L.) cultivation. To avoid or reduce various problems of importance to the crop, it facilitates the achievement of the cultivar's productive potential and the reduction of production costs. Thus, the objective of this work is to identify which conditions are suitable for evaluating germination in bean seeds using different substrates. The treatments were subjected to a temperature of 25 °C analyzing five substrates (germitest® paper; germitest® paper + sand; germitest® paper + soil; germitest® paper + charcoal and germitest® paper + vermiculite). The chemicals used were: Cruiser 350 FS, Fortenza 600 FS, Standak Top and Avicta complete. The most suitable substrate for installing the germination test in beans depends on the type of product and active ingredient of the seed treatment. Emphasizing the substrates germitest® + vermiculite and germitest®+soil, those that best performed positive characteristics when in contact with the chemical treatment.

Advances in Kombucha Tea Fermentation: A Review

Kombucha is a carbonated, slightly acidic beverage traditionally produced by the fermentation of sweetened tea by a symbiotic culture of bacteria and yeast (SCOBY). The microbial community of kombucha is a complex one, whose dynamics are still not fully understood; however, the emergence of culture-independent techniques has allowed a more comprehensive insight into kombucha microbiota. In recent times, advancements have been made towards the optimisation of the fermentation process, including the use of alternative substrates, defined starter cultures and the modification of fermentation parameters, with the aim of producing an innovative beverage that is improved in terms of its physiochemical, sensory and bioactive properties. The global kombucha market is rapidly increasing, with the rising popularity of the tea attributed in part to its purported health benefits, despite the lack of research in human subjects to substantiate such claims. Accordingly, the incidence of kombucha home-brewing has increased, meaning there is a requirement for individuals to recognise the potential hazards associated with fermentation and the relevant preventative measures to be undertaken to ensure the safe preparation of kombucha. The aim of this review is to provide an update regarding the current knowledge of kombucha production, microbiology, safety and marketing.

Modified hydroponics and phenolic foam as technological innovations in the production of coffee seedlings from cuttings

Brazilian coffee production represents an important activity in the country’s agricultural sector and, for this reason, it requires innovative technologies for the production of seedlings, which is one of the most important inputs in crop implantation. Thus, plant cloning by cutting, mineral nutrition via modified hydroponics and the use of alternative substrates appear as technological innovations for seedling production. This study evaluated the production of clonal coffee seedlings in a modified hydroponic system in comparison to the conventional climate-controlled greenhouse system, using vermiculite and phenolic foam as alternative substrates. At the end of the experiment, the seedlings were analyzed for growth (height, stem diameter, number of total leaves, leaf area, root area, shoot and root dry matter) and physiological (chlorophyll content and stomatal conductance) characteristics. For the statistical analysis, a completely randomized design was used in a factorial scheme 2 (types of substrate) x 2 (cultivation systems) with six replications and ten plants per plot. The innovative modified hydroponic system leads to a greater growth of coffee seedlings produced by cuttings in tubes with vermiculite compared to those produced in conventional systems. The substrate phenolic foam can be used alternatively in the air-conditioned greenhouse system. However, in the modified hydroponic system, it is not indicated, as it causes total seedling mortality.

Fundamental limitations in transferred CVD graphene caused by Cu catalyst surface morphology

The transfer of large-area graphene is a critical step in the development of technological applications, particularly when its structural integrity and physical properties are of central importance. While the scientific community dedicated a great deal of efforts improving the scalability and cleanliness of the transfer protocol, less research focused on the fundamental mechanisms responsible for the formation of cracks, wrinkles, corrugations, folds and mechanical strain which drastically hinder the reliability of the process. Here we describe how the surface morphology of copper, which serves as catalyst for the graphene chemical vapor deposition (CVD), significantly impacts (i) the transfer process reliability, (ii) graphene’s planar aspect, and (iii) graphene’s physical properties once transferred onto device-compatible substrates. We systematically compare the transfer of highly crystalline graphene from Cu foils, polycrystalline Cu films and epitaxial Cu films which possess a surface roughness spanning over 2 orders of magnitude. Our results suggest that, regardless of the transfer approach, the Cu template surface morphology is one of the major causes for the non optimal transfer results and discrepancies in physical properties reported in the literature. These findings provide valuable insights encouraging the use of alternative substrates when considering the integration of graphene into functional applications.

Metabolic Engineering of Lysine Producing Corynebacterium glutamicum Strains

The review is devoted to the analysis of the current achievements of Corynebacterium glutamicum metabolic engineering for the production of lysine. Key genes of lysine biosynthesis in C. glutamicum and ways of creating new genetically modified strains are considered. The role of different plasmids, vector cassettes, and promoter types for the regulation of gene expression in C. glutamicum is described. Information is provided on the use of carbon-containing substrates (hexose, pentose, lactic acid, mannitol) for the production of lysine. Possibilities of using CRISPR technology in genetic engineering of C. glutamicum are considered. Genetic changes in C. glutamicum allowed the use of alternative substrates and contributed to the increase of lysine accumulation in the culture fluid. The data that may be used for the creation of new lysine overproduction strains are summarized.

Immunometabolic Checkpoints of Treg Dynamics: Adaptation to Microenvironmental Opportunities and Challenges.

In the last decades, immunologists have started to consider intracellular metabolism in relation with the dynamics and functions of immune cells, especially when it became clear that microenvironmental alterations were associated with immune dysfunctions. Regulatory T cells (Tregs) are equipped with a variety of immunological and metabolic sensors, and encompass circulating as well as tissue-resident cells, being therefore particularly susceptible to microenvironmental cues. Moreover, Tregs undergo metabolic reprogramming over the course of an immune response, allowing the use of alternate substrates and engaging different metabolic pathways for energetic demands. The study of metabolic mechanisms supporting Treg dynamics has led to puzzling results, due to several limitations, including the heterogeneity of population in the same tissues and between different tissues, the difficulty in considering all the interconnected metabolic pathways during a cellular process, and the differences between in vitro and in vivo conditions. Therefore, Treg reliance on different metabolic routes (oxidation rather than glycolysis) has been a matter of controversy in recent years. Metabolic reprogramming and altered bioenergetics are now identified as hallmarks in cancer, and are employed by cancer cells to determine the availability of metabolites and molecules, thus affecting the fate of tumor-infiltrating immune cells. In particular, the tumor microenvironment forces a metabolic restriction and a plethora of synergistic intrinsic and extrinsic stresses, leading to an impaired anti-tumor immunity and favoring Treg generation, expansion, and suppressive function. This leads to the understanding that Tregs and conventional T cells have different capability to adapt to metabolic hurdles. Considering the role of Tregs in dictating the outcome of tumor-specific responses, it would be important to understand the specific Treg metabolic profile that provides an advantage at the tumor site, to finally identify new targets for therapy. In this review, we will report and discuss the major recent findings about the metabolic pathways required for Treg development, expansion, migration and functions, in relation to tissue-derived signals. We will focus on the adipose tissue and the liver, where Tregs are exposed to a variety of metabolites, and on the tumor microenvironment as the context where Tregs develop the ability to adapt to perturbations in nutrient accessibility.

Glucose-Induced Transcriptional Hysteresis: Role in Obesity, Metabolic Memory, Diabetes, and Aging.

During differentiation transient, inducers produce permanent changes in gene expression. A similar phenomenon, transcriptional hysteresis, produced by transient or prolonged exposure to glucose, leads to cumulative, persistent, and largely irreversible effects on glucose-regulated gene expression, and may drive key aspects of metabolic memory, obesity, diabetes, and aging, and explain the protective effects of dietary restriction during aging. The most relevant effects of glucose-induced transcriptional hysteresis are the persistent effects of elevated glucose on genes that control glucose metabolism itself. A key observation is that, as with the lac operon, glucose induces genes that promote glycolysis and inhibits gene expression of alternative metabolic pathways including the pentose pathway, beta oxidation, and the TCA cycle. A similar pattern of metabolic gene expression is observed during aging, suggesting that cumulative exposure to glucose during aging produces this metabolic shift. Conversely, dietary restriction, which increases lifespan and delays age-related impairments, produces the opposite metabolic profile, leading to a shift away from glycolysis and toward the use of alternative substrates, including lipid and ketone metabolisms. The effect of glucose on gene expression leads to a positive feedback loop that leads to metastable persistent expression of genes that promote glycolysis and inhibit alternative pathways, a phenomenon first observed in the regulation of the lac operon. On the other hand, this pattern of gene expression can also be inhibited by activation of peroxisome proliferator activating receptor transcription factors that promote beta oxidation and inhibit metabolism of glucose-derived carbon bonds in the TCA cycle. Several pathological consequences may arise from glucose-induced transcriptional hysteresis. First, elevated glucose induces glycolytic genes in pancreatic beta cells, which induces a semi-stable persistent increase in insulin secretion, which could drive obesity and insulin resistance, and also due to glucose toxicity could eventually lead to beta-cell decompensation and diabetes. Diabetic complications persist even after complete normalization of glucose, a phenomenon known as metabolic memory. This too can be explained by persistent bistable expression of glucose-induced glycolytic genes.

Evaluation of Korshinsk Peashrub (Caragana korshinskii Kom.) as a Substrate for the Cultivation of Pleurotus eryngii

The cultivation of Pleurotus eryngii is increasing rapidly in China due to its nutritional and medicinal importance, excellent flavor, and long shelf life; therefore, cheaper and locally available alternative substrates are urgently needed. Experiments were performed to investigate the use of alternative substrates for P. eryngii cultivation. Korshinsk peashrub (Caragana korshinskii Kom.), a perennial shrub, was included in the substrate at varying rates to substitute for the sawdust and sugarcane bagasse (21/38 and 21/35%, respectively) in the typical substrate. The cultivation substrate including 38% Korshinsk peashrub did not significantly affect linear mycelial growth. The fruit body yield (247.3 g/bag) and biological efficiency (70.66%) achieved by using this substrate were significantly higher than those achieved using the control substrate (229.6 g/bag and 65.59%). Crude polysaccharide content was highest (6.12%) in the mushroom grown on 38% Korshinsk peashrub substrate; in this mushroom, crude polysaccharide content was increased by 70.47% compared with that of the mushroom grown on the control substrate (3.59%). These results reveal that supplementing the substrate in which P. eryngii is grown with Korshinsk peashrub can improve polysaccharose accumulation by P. eryngii. The findings described above reveal that Korshinsk peashrub is an efficient, cost-effective, and promising substrate additive that can improve P. eryngii quality and yield while largely substituting for sawdust and sugarcane bagasse.

Screening of yeast isolates from flowers for effective ethanol production.

The use of alternative substrates to produce biofuel is a striking option nowadays. This study aimed to screen bioethanolproducing yeast strains. From different flowers, 65 yeasts were isolated. Twelve isolates assimilated glucose by liberation of CO 2 anaerobically. Out of these, only 5 yeast isolates fermented glucose in medium consisting of 0.8 g/L Mg2+ ions to produce 2.05 ± 0.03% ethanol. The selected five strains were identified as members of the genera Metschnikowia or Meyerozyma based on molecular characterization. Selected yeast strains were used for conversion of rice into bioethanol following dilute acid hydrolysis and fermentation. Consistent ethanol production was 1.80 ± 0.05% at days 2-4 by Metschnikowia cibodasensis Y34 and 2.20 ± 0.21% by Meyerozyma caribica Y42 at days 4-6 with a gradual decrease at the time of experiment termination (day 10). Metschnikowia cibodasensis Y34 and Meyerozyma caribica Y42 produced the highest ethanol at pH 3, i.e. 1.75 ± 0.14% at days 3 and 5 and 2.05 ± 0.14% at days 1 and 3, respectively, upon incubation with different pH levels and 1% NaCl. Growth and ethanol production at pH 4 and 5 was close to that at pH 3, with a slight increase in production by Metschnikowia cibodasensis Y34 at pH 4 up to day 3.

On mitochondrial metabolism in tumor biology.

To provide examples of mitochondria-specific metabolic events that influence tumor cell biology, and of metabolism-related mitochondrial biomarkers and therapeutic targets in cancer cells. Cancer cell mitochondria are rewired to optimally serve the cancer cell under various conditions of cellular stress. The nonexhaustive list of mitochondrial alterations that support cancer cell proliferation, survival, and/or progression includes upregulation of oxidative metabolism and use of alternative substrates, oncometabolites, increased superoxide production, mutated mitochondrial DNA, and altered mitochondrial morphology and dynamics. Potential therapeutic targets include fatty acid oxidation, voltage-dependent anion channel-1, the pyruvate dehydrogenase complex, and Complex I. Some phenotypical traits, for example, chemoresistance and metastasis, are likely regulated by a fine-tuned balance between several metabolic processes and events that are upregulated in parallel and are also dependent on microenvironmental cues. Many metabolism-related mitochondrial biomarkers show prognostic value, but the biological interpretation of the data may be confounded by the overall metabolic status and context. Understanding metabolic regulation of stemness is important for targeting cancer stem cells. Therapeutic targeting of cancer cell mitochondria remains experimental but promising, and more predictive markers will be needed for metabolism-based treatments and personalized medicine.

Uso de Paclobutrazol e esterco bovino melhora a qualidade das mudas de pimenta

The use of high quality seedlings is a key factor for the success of vegetable production. A high quality seedling may be obtained with the use of appropriate substrates and adequate nutritional and hormonal balance of the plants. An experiment was conducted to investigate the effects of foliar application of nitrogen and paclobutrazol and the use of cattle manure on production of pepper seedlings. Pepper seedlings (Capssicum frutescens cv. Malagueta) were grown in a seedling nursery with shadow protection at 50%. Treatments were arranged in a completely randomized design in a 2x3 factorial: two types of substrates [commercial substrate (Bioplant®) and alternative substrate composed of 50% cattle manure and 50% vermiculite] and three foliar treatments [10000 mg L-1 nitrogen (N); 50 mg L-1 paclobutrazol (PBZ); and 10000 mg L-1 N + 50 mg L-1 PBZ], with six replications. Foliar applications were performed at 21 days after sowing. Three categories of morphological indicators were measured, i.e., plant dimensions (height and diameter), plant dry matter (shoot, root and total dry matter) and indices (sturdiness quotient “SQ”, shoot:root dry matter ratio “SRR” and Dickson quality index “DQI”). The use of paclobutrazol, associated or not with nitrogen, and the use of alternative substrate consisting of 50% cattle manure and 50% vermiculite improved the quality of pepper seedlings, indicating they are excellent management strategies for the vegetable seedling production.

Novel Rhizosphere Soil Alleles for the Enzyme 1-Aminocyclopropane-1-Carboxylate Deaminase Queried for Function with an In Vivo Competition Assay.

Metagenomes derived from environmental microbiota encode a vast diversity of protein homologs. How this diversity impacts protein function can be explored through selection assays aimed to optimize function. While artificially generated gene sequence pools are typically used in selection assays, their usage may be limited because of technical or ethical reasons. Here, we investigate an alternative strategy, the use of soil microbial DNA as a starting point. We demonstrate this approach by optimizing the function of a widely occurring soil bacterial enzyme, 1-aminocyclopropane-1-carboxylate (ACC) deaminase. We identified a specific ACC deaminase domain region (ACCD-DR) that, when PCR amplified from the soil, produced a variant pool that we could swap into functional plasmids carrying ACC deaminase-encoding genes. Functional clones of ACC deaminase were selected for in a competition assay based on their capacity to provide nitrogen to Escherichia coli in vitro. The most successful ACCD-DR variants were identified after multiple rounds of selection by sequence analysis. We observed that previously identified essential active-site residues were fixed in the original unselected library and that additional residues went to fixation after selection. We identified a divergent essential residue whose presence hints at the possible use of alternative substrates and a cluster of neutral residues that did not influence ACCD performance. Using an artificial ACCD-DR variant library generated by DNA oligomer synthesis, we validated the same fixation patterns. Our study demonstrates that soil metagenomes are useful starting pools of protein-coding-gene diversity that can be utilized for protein optimization and functional characterization when synthetic libraries are not appropriate.

Forming stakeholder alliances to unlock alternative and unused biomass potentials in bioenergy regions

In recent discussions on renewable energy, bioenergy is strongly linked to the extended cultivation of maize as energy crop and often coincides with negative public perception. However, the 2014 amendment to the 2012 version of the EEG puts an increased focus on the use of alternative substrates and residual biomass for bioenergy production, which could result in improved sustainability impacts. In this paper, we focus on the potentials of so-called alternative biomass and explore how these types of biomass can be embedded into a sustainable management of both the landscape and the energy system. In particular, we address the question of how alternative and unused biomass potentials can be made available for regionally embedded, sustainable bioenergy solutions. Based on GIS analyses of regional biomass potentials we discuss this approach in a transdisciplinary study focussing on the Northwestern part of Germany located close to the North Sea border. Two case studies comprising a total of three biogas plants are examined, of which one is located directly at the North Sea coast (maritime case study) and the other facing an inland (terrestrial) situation. The GIS analyses of these two studied areas reveal substantial potentials of alternative biomass, which are not exploited thus far. Results of the assessment and possible participatory actions of various stakeholders and their benefits are discussed, focussing on higher shares of regional biomass for bioenergy production. This study stresses the importance of achieving integration and participation of a variety of actors along the entire bioenergy supply network and highlights the need for cross-sectoral collaboration in order to exploit the identified alternative biomass potentials and thus improve the sustainability impact of bioenergy production.

Alternative substrates in the production of lettuce seedlings and their productivity in the field

Based on the hypothesis that alternative substrates should improve the yield of lettuce crops by producing better quality seedlings, the objective of this work was to evaluate the effect of different substrates on the production of seedlings of this species, and their growth in the field. The study was in two stages. The first consisted of the production of lettuce seedlings, and the second assessed their development in the field. Four alternative substrates were tested, obtained by mixing together a sieved vermicompost from which all clumps had been removed, sterilized sand, charred rice husks and basalt powder. The commercial substrate, Plantmax HA®, was also tested. In the first phase, which was conducted in a completely randomised design with four replications, the height, root length, number of leaves, leaf area and dry weight of the seedlings were all evaluated 28 days after sowing. In the second phase, which was carried out in the field in a randomised block design with four replications, the plants were harvested 50 days after transplanting and the head diameter, fresh weight, number of leaves and leaf and stem dry weight were evaluated. The alternative substrates produced larger seedlings in less time than the commercial substrate, resulting in a reduction of 10 days in the total crop cycle. The reduction in the time between sowing and harvesting, together with those aspects relating to sustainability, are the main advantages of the use of alternative substrates, since in the field crop production did not differ between treatments.

Advances in improving mammalian cells metabolism for recombinant protein production

Background: The production of recombinant proteins for therapeutic use represents a great impact on the biotechnology industry. In this context, established mammalian cell lines, especially CHO cells, have become a standard system for the production of such proteins. Their ability to properly configure and excrete proteins in functional form is an enormous advantage which should be contrasted with their inherent technological limitations. These cell systems exhibit a metabolic behaviour associated with elevated cell proliferation which involves a high consumption of glucose and glutamine, resulting in the rapid depletion of these nutrients in the medium and the accumulation of ammonium and lactate. Both phenomena contribute to the limitation of cell growth, the triggering of apoptotic processes and the loss of quality of the recombinant protein. Results: In this review, the use of alternative substrates and genetic modifications (host cell engineering) are analyzed as tools to overcome those limitations. In general, the results obtained are promising. However, metabolic and physiological phenomena involved in CHO cells are still barely understood. Thus, most of publications are focused on specific modifications rather than giving a systemic perspective. Conclusions: A deeper insight in the integrated understanding of metabolism and cell mechanisms is required in order to define complementary strategies at these two levels, so providing effective means to control nutrients consumption, reduce by-products and increase process productivity.

Polyhydroxy Alkanoates - A Sustainable Alternative to Petro-Based Plastics

Industrial growth, urbanization and wrong agricultural practices are responsible for pollution and loss of environmental quality. Petro plastics, produced from mineral resources, are one of the most important materials, but the production process destructs the environment. Bio-based and biodegradable plastics can form the basis for environmentally preferable and sustainable alternative to current materials based exclusively on petroleum feed stocks. Bioplastic helps us to overcome the problem of pollution caused by synthetic plastics as they originate from renewable resources and are a new generation of plastics able to significantly reduce the environmental impact in terms of energy consumption and greenhouse effect. Polyhydroxyalkanoate (PHA) emerges as a potential candidate in a way to be used as a biopolymer material which not only possesses the characteristic similar to the traditional plastic, but it is also biodegradable in nature without any toxic production .A way to reduce the production cost is the use of alternative substrates, such as the agro industrial wastes. This review gives an overview of economical strategies to reduce production costs of PHA as well as its applications in various fields.