Specific Cultivation Conditions Research Articles

An artificial neuronal network coupled with a genetic algorithm to optimise the production of unsaturated fatty acids in Parachlorella kessleri

In this study, an Artificial Neural Network-Genetic Algorithm (ANN-GA) approach was successfully applied to optimise the physicochemical factors influencing the synthesis of unsaturated fatty acids (UFAs) in the microalgae P. kessleri UCM 001. The optimized model recommended specific cultivation conditions, including glucose at 29 g/L, NaNO3 at 2.4 g/L, K2HPO4 at 0.4 g/L, red LED light, an intensity of 1000 lx, and an 8:16-h light-dark cycle. Through ANN-GA optimisation, a remarkable 66.79% increase in UFAs production in P. kessleri UCM 001 was achieved, compared to previous studies. This underscores the potential of this technology for enhancing valuable lipid production. Sequential variations in the application of physicochemical factors during microalgae culture under mixotrophic conditions, as optimized by ANN-GA, induced alterations in UFAs production and composition in P. kessleri UCM 001. This suggests the feasibility of tailoring the lipid profile of microalgae to obtain specific lipids for diverse industrial applications. The microalgae were isolated from a high-mountain lake in Colombia, highlighting their adaptation to extreme conditions. This underscores their potential for sustainable lipid and biomaterial production. This study demonstrates the effectiveness of using ANN-GA technology to optimise UFAs production in microalgae, offering a promising avenue for obtaining valuable lipids. The microalgae's unique origin in a high-mountain environment in Colombia emphasises the importance of exploring and harnessing microbial resources in distinctive geographical regions for biotechnological applications.

RESEARCH ON THE MANAGEMENT OF THE MAIN CHEMICAL PROPERTIES OF CHROMIC LUVISOLS FROM FARMS/HOUSEHOLDS AGRITOURISTIC IN DOLJ, IN THE PERIOD 1995-2021

The research addresses an original and complex topic concerning the evolution of the main chemical properties of the chromic luvisols in the southwestern part of Romania, in Dolj County, exploited under the specific cultivation conditions of agritourist farms. The novelty of this research consists in the multidisciplinary interpretation of the analyses on chemical properties and their influence on the quality and quantity of agricultural productions. In the second part, the main chemical properties of the chromic luvisols were analysed, both for the soil developed under woody vegetation, and both for the cultivated soils. Comparing the results of the analyses, we found that the natural fertility of the cultivated soil decreased considerably, which led to a significant deterioration of the main chemical properties, precisely due to cultivation. In the third part, a study was carried out on the presence and concentration of heavy metals in this type of soil, finding from the interpretation of the analyses that the values of all the studied elements fall below the alert threshold. he recommendation on the researched aspects is that in order to limit the degradation and even improve the main chemical properties of chromic luvisols, in the agritourism farms, an ecological agriculture must be practiced.

Deciphering the growth responses and genotypic diversity of bioluminescent Photobacterium phosphoreum on chicken meat during aerobic refrigerated storage

The advent of high-throughput sequencing technologies in recent years has revealed the unexpected presence of genus Photobacterium within the chicken meat spoilage ecosystem. This study was undertaken to decipher the occurrence, the growth patterns and the genotypic biodiversity of Photobacterium phosphoreum on chicken breast fillets stored aerobically at 4 °C through conventional microbiological methods and molecular techniques. Samples were periodically cultured on marine broth agar (MA; supplemented with meat extract and vancomycin) for the enumeration of presumptive bioluminescent Photobacterium spp. In total, 90 bioluminescent bacteria were recovered from the initial (time of first appearance), middle and end stages of storage. Concomitantly, 95 total psychrotrophic/psychrophilic bacteria were isolated from the same medium to assess the presence and diversity of non-luminous photobacteria. Genetic diversity between bioluminescent isolates was assessed with two PCR-based DNA fingerprinting methods, i.e. RAPD and rep-PCR. Moreover, the characterization of selected bacterial isolates at the genus and/or species level was performed by sequencing of the 16S rRNA and/or gyrB gene. Bioluminescent bacteria were scarcely encountered in fresh samples at population levels of ca. 2.0 log CFU/g, whilst total psychrotrophic/psychrophilic bacteria were found at levels of ca. 4.4 log CFU/g. As time proceeded and close to shelf-life end, bioluminescent bacteria were encountered at higher populations, and were found at levels of 5.3 and 7.0 log CFU/g in samples from the second and third batch, respectively. In the first batch their presence was occasional and at levels up to 3.9 log CFU/g. Accordingly, total psychrotrophic/psychrophilic bacteria exceeded 8.4 log CFU/g at the end of storage, suggesting the possible underestimation of bioluminescent populations following the specific cultivation conditions. Sequence analysis assigned bioluminescent isolates to Photobacterium phosphoreum, while genetic fingerprinting revealed high intra-species variability. Respectively, total psychrotrophs/psychrophiles were assigned to genera Pseudomonas, Shewanella, Psychrobacter, Acinetobacter, Vibrio and Photobacterium. Non-luminous photobacteria were not identified within the psychrotrophs/psychrophiles. Results of the present study reveal the intra- and inter-batch variability on the occurrence and growth responses of P. phosphoreum and highlight its potential role in the chicken meat spoilage consortium.

Identification of Seven Key Structural Genes in the Anthocyanin Biosynthesis Pathway in Sepals of Hydrangea macrophylla.

Under specific cultivation conditions, the sepal color of Hydrangea macrophylla (H. macrophylla) changes from red to blue due to the complexation of aluminum ions (Al3+), delphinidin 3-glucoside, and copigments. However, this phenomenon cannot occur in all cultivars despite the presence of sufficient Al3+ and copigments. To explore the mechanism of sepal bluing in H. macrophylla, there is an urgent need to study the molecular regulation of the anthocyanin biosynthesis pathway. However, the key structural genes, other than CHS, regulating anthocyanin biosynthesis in the sepals of H. macrophylla have not been identified. In this study, based on full-length transcriptome data from H. macrophylla ‘Bailmer’, the key structural genes regulating anthocyanin biosynthesis in the sepals of H. macrophylla were isolated and investigated. Ultimately, seven key structural genes, HmCHS1, HmCHI, HmF3H1, HmF3′H1, HmF3′5′H, HmDFR2, and HmANS3, were demonstrated to show high expression levels in colored sepals. The expression levels of these seven genes increased gradually with the development of sepals and were highest in the full-bloom stage. The trend of gene expression was consistent with the trend of anthocyanin contents. It was concluded that the seven selected genes were involved in anthocyanin biosynthesis in the sepals of H. macrophylla. The full-length sequence data have been deposited into the NCBI Sequence Read Archive (SRA) with accession number PRJNA849710. This study lays a good foundation for the further elucidation of the molecular mechanism of sepal coloration in H. macrophylla.

Evaluation of spring soft wheat varieties and zonal features of seed production in the Altai Territory

One of the leading grain crops in Russia is spring wheat. This is a strategic food crop of our country; it is also an important component in the structure of forage crops for monogastric animals, such as pigs and poultry. The purpose of the research was to evaluate spring soft wheat varieties of different maturity groups in order to identify genotypes as the starting material for obtaining varieties adapted to the cultivation zones, and to determine the areas optimal for the production of grain for seed purposes with high quality indicators. Field studies have been carried out in three ecologically different zones: the Priobskaya zone, the Prialtaiskaya zone, and the Prisalairskaya zone. Under the conditions of the Altai Territory, genetic sources of spring soft wheat have been identifi ed for different soil and climatic parameters of the study zones, the use of which will allow obtaining high-yielding varieties with high quality grain for specific cultivation conditions. The variability of the indicators of the characteristics of varieties in three ecologically different zones has been determined. The indicators of adaptability and stability of spring soft wheat varieties in different zones of cultivation have been determined. The optimal zones for conducting breeding work and seed production of varieties have been identifi ed. New scientific data on the quality parameters of seed grain in various agro-climatic zones of the Altai Territory have been obtained. The share of the contribution of the factors “variety”, “year”, “environment” to the variability of grain quality characteristics has been established. The economic efficiency of cultivating varieties of spring soft wheat for the production of high-quality seed grain has been determined.

Seemingly trivial secondary factors may determine microbial competition: a cautionary tale on the impact of iron supplementation through corrosion.

ABSTRACTMicrobial community engineering aims for enrichment of a specific microbial trait by imposing specific cultivation conditions. This work demonstrates that things may be more complicated than typically presumed and that microbial competition can be affected by seemingly insignificant variables, like in this case the type of acid used for pH control. Aerobic bioreactors pulse fed with acetate operated with hydrochloric acid resulted in the enrichment of Plasticicumulans acidivorans, and changing the pH controlling agent to sulfuric acid shifted the community towards Zoogloea sp. Further research demonstrated that the change in community structure was not directly caused by the change in acid used for pH control, but resulted from the difference in corrosive strength of both acids and the related iron leaching from the bioreactor piping. Neither system was iron deficient, suggesting that the biological availability of iron is affected by the leaching process. Our results demonstrate that microbial competition and process development can be affected dramatically by secondary factors related to nutrient supply and bioavailability, and is way more complex than generally assumed in a single carbon substrate limited process.

Quality indicators and nitrate accumulation in winter wheat grain when applying fertilizers in conditions of plain irrigated zone of Dagestan

The introduction of new highly productive high-impact varieties into production requires a revision of the rules and methods of fertilizer application in relation to these varieties' possibilities under specific cultivation conditions. Thus, the studies carried out on meadow-chestnut soil in the conditions of the flat irrigated zone of Dagestan in the study of new zoned winter wheat varieties Bezostaya 100 and Sila showed high productivity in the application of N90P45 fertilizers. The aim of the research was to study grain quality indicators and nitrate accumulation of the main food crop in the systemic application of fertilizers. In this article we present the scientific research results on the dependence of yield, protein, and gluten of new winter wheat varieties on the mineral fertilizers' application. The dependence of nitrate accumulation in winter wheat grain on mineral fertilizers' introduction was revealed.

Prosopis juliflora peroxidases for phenol remediation from industrial wastewater — An innovative practice for environmental sustainability

Prosopis juliflora or Mesquite, one of the world’s worst invaders, yields low-purity peroxidases (MPx), which remove phenols from the wastewater of textile and leather industries. Within 30 min, MPx removes phenols from wastewater of the textile industry (94.95 ± 0.82%) and leather industry (91.49 ± 1.54%). After treatment with MPx, the residual phenol in the wastewater remained much below the environmentally safe limit outlined by the USEPA. For maximum phenols removal, MPx requires 4–6 mM H2O2, whereas Horseradish peroxidase (HRP), a commercially available and the most widely used peroxidase, uses 8 mM H2O2. MPx perform better than (HRP), in parameters such as phenol removal efficiency, need of chemical additive, stability, and time of preparation. MPx, therefore, offer an economically viable method for wastewater treatment and also obviate several challenges of using purified enzymes. Extraction from the non-edible invasive plant is an added benefit as it does not require specific cultivation conditions and address the concern of competing with food resource. Further, using an invasive plant as a bioresource will help in the management of aggressive invaders like P. julifora. We report a procedure to prepare MPx with a lesser number of chemicals and use it with a low concentration of H2O2 for remediation of phenol from industrial wastewater. MPx, with high phenol removal capacity, shows the potential to act as an economic but effective alternative to purified peroxidases for environmental remediation withstanding the principles of the circular economy.

Phytotechnical parameters and yield of watermelon plants under different irrigation and nitrogen levels

Water and nitrogen availability are fundamental for obtaining a high yield of the watermelon plant. However, the appropriate levels of irrigation and nitrogen to be applied according to specific cultivation conditions should be previously determined. The objective of the present study was to evaluate the effects of irrigation and nitrogen levels in fertigation on the phytotechnical parameters and yield of the Top Gun hybrid watermelon plant. The experiment was conducted at São Luiz Ranch, in Bom Jesus (PI), from August 4 to October 15, 2015. The blocks in strips experimental design was used with four repetitions, and the treatments consisted of five irrigation depths (114.17, 156.86, 221.16, 268.87, and 317.09 mm) and five doses of nitrogen in fertigation (0, 50, 100, 150, and 200 kg ha-1). The growth rate of the main and primary branches, leaf area, specific leaf area, stem diameter, dry mass of the aerial part, number of fruits, and commercial production per plant were evaluated. Both hydric and nutritional stress caused decreased growth rates, leaf areas, and specific leaf areas, and the highest growth expressions were found with the combination of a 317.09 mm irrigation depth and 200 kg ha-1 nitrogen. The irrigation depths did not influence the diameter of the stem nor the accumulation of dry mass. Nitrogen doses did not influence the number of fruits and production. The 247.95 mm irrigation depth promoted the highest commercial fruit production of the watermelon plant.

Squalene lipotoxicity in a lipid droplet-less yeast mutant is linked to plasma membrane dysfunction.

Squalene is a naturally occurring triterpene with wide industrial applications. Due to limited natural resources, production of this valuable lipid in yeast is of high commercial relevance. Typically low levels of squalene in yeast can be significantly increased by specific cultivation conditions or genetic modifications. Under normal conditions, excess squalene is stored in lipid droplets (LD), while in a Saccharomyces cerevisiae mutant unable to form LD it is distributed to cellular membranes. We present here the evidence that squalene accumulation in this LD-less mutant treated with squalene monooxygenase inhibitor terbinafine induces growth defects and loss of viability. We show that plasma membrane malfunction is involved in squalene toxicity. We have found that subinhibitory concentrations of terbinafine increased the sensitivity of LD-less mutant to several membrane-active substances. Furthermore, squalene accumulation in terbinafine-treated LD-less cells disturbed the maintenance of membrane potential and increased plasma membrane permeability to rhodamine 6G. LD-less cells treated with terbinafine showed also high sensitivity to osmotic stress. To confirm the causal relationship between squalene accumulation, loss of viability and impaired plasma membrane functions we treated LD-less cells simultaneously with terbinafine and squalene synthase inhibitor zaragozic acid. Reduction of squalene levels by zaragozic acid improved cell growth and viability and decreased plasma membrane permeability to rhodamine 6G in terbinafine-treated LD-less cells. Our results support the hypothesis that plasma membrane malfunction is involved in the mechanisms of squalene lipotoxicity in yeast cells with defective lipid storage.

Development of the leaf area and the productivity structure of the sunflower hybrids in the north-eastern Forest-Steppe of Ukraine

At the present stage, the model of leaf plant development is increasingly considered as the main element of genotypes adaptation to specific cultivation conditions, geographical area, etc. Under these conditions, the potential of the hybrid, the range of its adaptation to environmental conditions is determined by the level of interaction between the development of the assimilation apparatus and the generative organs. An urgent task aimed at improving the productivity of sunflower crop due to the use of genotypes adapted to the conditions of the north-eastern Forest-Steppe and Polyssya of Ukraine is to identify typical schemes of interaction of photosynthetic potential and parameters of plant productivity and crop yields.
 The studies were conducted in accordance with the program for the development of a variety model for the conditions of the north-eastern Forest-Steppe and Polyssya of Ukraine. Field experiments were carried out in 2016‒2019 at the Sumy National Agrarian University and the Institute of the Agriculture of North East of Ukraine. In the studies, 28‒56 hybrids of different originators were tested annually. Sunflower was cultivated according to the technology recommended for the area, with pre-harvesting density of 60 thousand plants / ha. Harvesting was done manually, from two central rows of a 4-rows plot. The results were processed using the Statistics package. 
 The data on yield indices and values of leaf area coefficient (LAC) of crop for groups of varieties separated by the duration of growing season were analyzed. It was found that the increasing of leaf area was accompanied by an increasing of yield in case of comparing groups with dates of technological maturation until 20 August, 1 September and 10 September. In all cases, the maximum value of the leaf area index ranged from 3.12‒3.52 m2/m2. These dynamics of indicators indicated to the regulatory nature of the values of leaf area coefficient (LAC) of modern sunflower crop and the absence of genotypes (or conditions) capable of maintaining these values at the level of more than 3.3‒3.5 m2/m2.
 According to the analysis of correlation pleiades, the presence of several levels was found and the relative independence of the relationships between the group of parameters, determining the morphological structure of plants and the vertical structure of crop and the group of parameters, characterizing the content of chlorophyll and its concentration per unit area of leaf surface. In practical terms, the results of the analysis indicated the potential informative nature of the complex use of parameters characterizing the morpho-structure of plants, primarily the index of leaf area and the index of chlorophyll concentration per unit area.
 In order to isolate the typical schemes characteristic of different levels of adaptation to the conditions of the zone, data on 29 sunflower hybrids distributed in the region were clustered. The results of the analysis allowed to distinguish three significantly different algorithms for the realization of the vegetative and generative potential of sunflower hybrids in the area of the north-eastern Forest-Steppe of Ukraine. It has been established that one of the factors for successful realization of the generative potential of sunflower hybrids in the conditions of the zone is the ability to preserve and (in some cases) to improve the structure of relations between the dynamics and parameters of the plant leaf apparatus and the parameters of their generative development.

Multi-scale land-use disaggregation modelling: Concept and application to EU countries

Changes of carbon stocks in agricultural soils, emissions of greenhouse gases from agriculture, and the delivery of ecosystem services of agricultural landscapes depend on combinations of land-use, livestock density, farming practices, climate and soil types. Many environmental processes are highly non-linear. If the analysis of the environmental impact is based on data at a relatively coarse-scale (e.g. farm, country, or large administrative regions), conclusions can be misleading. For an accurate assessment of agri-environmental indicators, data of agricultural activities and their dynamics are needed at high spatial resolution. In this paper, we develop and validate a spatial model for predicting the agricultural land-use areas within the homogenous spatial units (HSUs). For the EU-28 countries, we distinguish about 1.5 × 105 HSUs and we consider 30 possible land-uses to match with the classification used in the Common Agricultural Policy Regionalized Impact (CAPRI) model. The comparison of model predictions with independent observations and with a simple rule-based approach at HSU level demonstrates that the predictions are generally accurate in more than 75 % of HSUs. The frequent crops or land-use are better predicted. For non-frequent crops and/or crops requiring specific cultivation conditions, the model needs further fine-tuning.

Recent Advances and Future Direction in Lyophilisation and Desiccation of Mesenchymal Stem Cells.

Mesenchymal Stem Cells (MSCs) are a promising mammalian cell type as they can be used for the reconstruction of human tissues and organs. MSCs are shown to form bone, cartilage, fat, and muscle-like cells under specific cultivation conditions. Current technology of MSCs cryopreservation has significant disadvantages. Alternative technologies of mammalian cells preservation through lyophilisation or desiccation (air-drying) are among the upcoming domains of investigation in the field of cryobiology. Different protectants and their combinations were studied in this context. Loading of the protectant in the live cell can be a challenging issue but recent studies have shown encouraging results. This paper deals with a review of the protectants, methods of their delivery, and physical boundary conditions adopted for the desiccation and lyophilisation of mammalian cells, including MSCs. A hybrid technique combining both methods is also proposed as a promising way of MSCs dry preservation.

Study of allelic composition of Vrn-1 and Ppd-1 genes in early–ripening and middle–early varieties of spring soft wheat in siberia

Using allele-specific primers, a combination of the Vrn-A1, Vrn-B1, Vrn-D1, Ppd-D1, and Ppd-B1 alleles was analyzed in 48 early-ripening and middle–early varieties of the spring soft wheat from different breeding centers of Siberia. Six haplotypes were detected, including two most widespread with two dominant genes (Vrn-A1 and Vrn-B1) on the background of recessivePpd-D1b gene (causing sensitivity to the photoperiod). The dominant Ppd-D1a allele was found in combination with dominant Vrn-A1 and Vrn-B1 genes only in one variety (Tulun 15), which is the earliest among all the analyzed varieties. A significant variability in the duration of vegetation was detected within each haplotype assuming a strong influence of the genetic background on the given trait. The results obtained can be used in marker-assisted selection of the most optimal genotypes for specific cultivation conditions.

Mesenchymal stem cell therapy in nonhematopoietic diseases.

The extensive clinical experiments with stem cells, particularly in the treatment of oncohematological diseases, opened up the possibility of trying out stem cells with nonhematopoietic diseases. Mesenchymal stem cells (MSCs) subsequently emerged as a promising source for the regeneration and repair of various tissues in the treatment of a range of diseases due to their presence in all derived mesenchymal tissues in the adult solid organs as well as in mesoderm from embryonic tissue. This, plus their pluripotentiality and the fact that they were easily obtainable, meant that MSCs represented an important source for studies in regenerative medicine. MSCs have been shown to be capable of differentiating in various types of mesoderm derived cells as well as ectoderm cells, such as skeletal muscle cells, neurons, cardiomyocytes, osteocytes, chondrocytes, and others. MSCs in specific cultivation conditions in vitro and in host transplanted tissue, being niche dependent, arouse clinical interest in stem-cell therapy for regeneration in nonhematopoietic tissue diseases and the prospect of creating a mesenchymal stem-cell bank for research and subsequent clinical use. In the development of clinical models, always preceded by preclinical studies, there are various requirements to guarantee the safety of therapy with stem cells and their products, including the GMP procedures, cytogenetic control, identification and characterization of cells by immune cytometric analysis, and demonstration of their pluripotentiality for the prospective use of MSC for tissue regeneration in nonhematopoietic diseases [1]. In the study of MSCs, the intrinsic properties—molecular, immunocytochemistry, isolation, expansion, differentiation, and cryopreservation—have made great advances and need further discussion. The fact that MSCs do not express the antigens of histocompatibility means that they can be used in allogeneic transplantation. The development of methods for isolating the subpopulations of MSC fractions together with the perspective with this subpopulation could obtain better results than the total population in replacement therapy for correction of determined specific function [2]. Researchers and physicians are looking into the physiopathology of some diseases in light of the intrinsic cell conditions on the development of each disease and are proposing therapies based on the cells themselves or on cell-based products. Some diseases are triggered in their physiopathology by autoimmune mechanisms that could be stabilized with the paracrine effects of MSCs, such as the anti-inflammatory effect [3]; other diseases are triggered by the senescence of the cells, as in conditions of cellular apoptosis, and the MSC cells could act with the paracrine effects such as antiapoptosis and by cell replacement; there are some diseases which result from the loss of the production of certain molecules and MSCs could differentiate in cells capable of producing the molecule [4]; in other diseases, there is an interruption in signals between the tissue cells, and the MSC paracrine effects could promote the connections through the production of growth factors [5]. On the other hand, in ischemic diseases, MSCs could be differentiated in specific types of specialized cells, such as vessels and contractile cells, cardiomyocytes [6]; in genetic diseases, MSCs could ensure the delivery of genes for gene therapy [7] and could act in immunomodulation with vaccines [8]. This issue provides discussions of the points described above and takes a look into the future of cell therapy in nonhematopoetic diseases, showing that it is nearer than we expect! It is reality! Katherine Athayde Teixeira de Carvalho Gustav Steinhoff Juan Carlos Chachques

Oxalic acid production by citric acid-producing Aspergillus niger overexpressing the oxaloacetate hydrolase gene oahA

The filamentous fungus Aspergillus niger is used worldwide in the industrial production of citric acid. However, under specific cultivation conditions, citric acid-producing strains of A. niger accumulate oxalic acid as a by-product. Oxalic acid is used as a chelator, detergent, or tanning agent. Here, we sought to develop oxalic acid hyperproducers using A. niger as a host. To generate oxalic acid hyperproducers by metabolic engineering, transformants overexpressing the oahA gene, encoding oxaloacetate hydrolase (OAH; EC 3.7.1.1), were constructed in citric acid-producing A. niger WU-2223L as a host. The oxalic acid production capacity of this strain was examined by cultivation of EOAH-1 under conditions appropriate for oxalic acid production with 30 g/l glucose as a carbon source. Under all the cultivation conditions tested, the amount of oxalic acid produced by EOAH-1, a representative oahA-overexpressing transformant, exceeded that produced by A. niger WU-2223L. A. niger WU-2223L and EOAH-1 produced 15.6 and 28.9 g/l oxalic acid, respectively, during the 12-day cultivation period. The yield of oxalic acid for EOAH-1 was 64.2 % of the maximum theoretical yield. Our method for oxalic acid production gave the highest yield of any study reported to date. Therefore, we succeeded in generating oxalic acid hyperproducers by overexpressing a single gene, i.e., oahA, in citric acid-producing A. niger as a host.

Microorganisms as sources of oils

A number of microorganism belonging to the genera of yeast, fungi, bacteria and microalgae have ability to accumulate substantial amounts of oil, sometimes up to an even in excess of 70% of their biomass weight under specific cultivation conditions. For nearly 100 years, the commercial opportunities of using microorganisms as sources of oils have been continuously examined. Although it was evident that microbial oils could never compete commercially with the major commodity plant oils, there were commercially opportunities for the production of some of the higher valued oils. Today, with the great progress of metabolic and genetic engineering, the developments are focus on the high value oils containing important polyunsaturated or specific fatty acids. Such oils have the potential to be used in different applications area as food, feed and oleochemistry. This review is covering the related researches about different oleaginous microorganisms for lipids production and microbial oils biosynthesis process. In add, the lipid metabolism, metabolic engineering strategies to increase lipid production and the economics of microbial oils production are introduced.

Microbial lipids from renewable resources: production and characterization

A number of microorganisms belonging to the genera of algae, yeast, bacteria, and fungi have ability to accumulate neutral lipids under specific cultivation conditions. The microbial lipids contain high fractions of polyunsaturated fatty acids and have the potential to serve as a source of significant quantities of transportation fuels. This paper reviews the current state of the art of this field. It summarizes the various microorganism used, feed stocks available, environmental factors that influence growth of cells and accumulation of lipids, major fatty acid composition of lipids, and the technology.

Physiological relation between respiration activity and heterologous expression of selected benzoylformate decarboxylase variants in Escherichia coli.

BackgroundThe benzoylformate decarboxylase (BFD) from Pseudomonas putida is a biotechnologically interesting biocatalyst. It catalyses the formation of chiral 2-hydroxy ketones, which are important building blocks for stereoselective syntheses. To optimise the enzyme function often the amino acid composition is modified to improve the performance of the enzyme. So far it was assumed that a relatively small modification of the amino acid composition of a protein does not significantly influence the level of expression or media requirements. To determine, which effects these modifications might have on cultivation and product formation, six different BFD-variants with one or two altered amino acids and the wild type BFD were expressed in Escherichia coli SG13009 pKK233-2. The oxygen transfer rate (OTR) as parameter for growth and metabolic activity of the different E. coli clones was monitored on-line in LB, TB and modified PanG mineral medium with the Respiratory Activity MOnitoring System (RAMOS).ResultsAlthough the E. coli clones were genetically nearly identical, the kinetics of their metabolic activity surprisingly differed in the standard media applied. Three different types of OTR curves could be distinguished. Whereas the first type (clones expressing Leu476Pro-Ser181Thr or Leu476Pro) had typical OTR curves, the second type (clones expressing the wild type BFD, Ser181Thr or His281Ala) showed an early drop of OTR in LB and TB medium and a drastically reduced maximum OTR in modified PanG mineral medium. The third type (clone expressing Leu476Gln) behaved variable. Depending on the cultivation conditions, its OTR curve was similar to the first or the second type. It was shown, that the kinetics of the metabolic activity of the first type depended on the concentration of thiamine, which is a cofactor of BFD, in the medium. It was demonstrated that the cofactor binding strength of the different BFD-variants correlated with the differences in metabolic activity of their respective host strain.ConclusionsThe BFD-variants with high cofactor binding affinity (wild type, His281Ala, Ser181Thr) obviously extract thiamine from the medium and bind it tightly to the enzyme. This might explain the hampered growth of these clones. In contrast, growth of clones expressing variants with low cofactor binding affinity (Leu476His, Leu476Pro, Leu476Pro-Ser181Thr) is not impaired. Leu476Gln has an intermediate cofactor binding strength, thus, growth of its host strain depends on the specific cultivation conditions. This paper shows that slight differences of the amino acid composition can affect protein expression and cultivation and might require an adaptation of media components. Effects such as the observed are hardly foreseeable and difficult to detect in conventional screening processes. Via small scale experiments with on-line measurements in shake flasks such effects influencing the cultivation and product formation can be detected and avoided.

COMPARING FRIGO AND FRESH PLANTS IN NON-FUMIGATED AND HEAVY SOIL: THE RESPONSE OF 10 STRAWBERRY GENOTYPES

Frigo and fresh plants are two types of plants used in Italy for annual strawberry plantations. Frigo plants are mostly used in the central northern areas of Italy, while the use of fresh plants is now increasing a lot in southern strawberry production areas. The aim of this work was the evaluation of frigo and fresh plant adaptability of 10 strawberry genotypes ('Adria', 'Alba', 'Clery', 'Irma', 'Onda' and 'Sveva', 'AN97.120.52', 'AN99.78.51', '97.129.11' and '98.86.6') to non-fumigated, chalky and clay soil. For two production cycles (2006 and 2007), frigo and fresh plants of each genotype were planted in the last week of July, including three replications of 10 plants, for genotype and type of plants. The plant-genotype effect was studied by detecting plant grow (number of shoot, leaves, leaf petiole length), plant productivity (total commercial production and fruit weight) and fruit quality (colour, firmness, soluble solids and titratable acidity). To these specific cultivation conditions, fresh plants resulted with a very low adaptability in comparison to frigo, for all genotypes tested.