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Identification and characterisation of the zooplankton genus Tigriopus as a natural source of astaxanthin and high-value fatty acids (EPA and DHA)
Get PDFCarotenoids are molecules involved in essential physiological processes in humans. For
this reason, the biotech industry constantly seeks to develop new methods to produce
these molecules. This thesis is part of the LEAF (LutEin Algae Feasibility) project,
whose initial objective was to cultivate lutein-rich microalgae and collect them using
zooplankton as a more cost-effective alternative to the marigold flower. However, our
results suggest that this method, using the microalgae species Dunaliella salina and the
zooplankton species Artemia franciscana, produces limited amounts of lutein and with
low purity. Therefore, we reoriented our work to characterize the marine harpacticoid
copepod Tigriopus californicus. This species does not limit itself to accumulating
metabolites of interest such as Artemia, but produces them from ingested or selfmanufactured
precursors. Specifically, Tigriopus synthetizes the carotenoid astaxanthin
and the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic
acid).
Our feeding experiments confirmed that T. californicus assimilated carotenoids from all
the feed sources used and converted them into astaxanthin. In addition, T.
californicus used short-chain fatty acids to produce and accumulate EPA and DHA.
Specifically, T. californicus produced the highest amounts of astaxanthin, EPA and
DHA (1.53 mg g-1, 0.139 μg g-1 and 0.204 μg g-1 of dry mass, respectively),
when Nannochloropsis oceanica was used as a food source (p <0.05 when compared
with the other diets). Of note, T. californicus produced 0.098 μg of DHA per g of dry
biomass when fed with baker's yeast (which does not have alpha-linolenic acid,
essential in animals to synthesize DHA), suggesting that Tigriopus can synthesize DHA
de novo.
Exposure of T. californicus to abiotic stimuli suggests, as has been reported by other
authors, that light and temperature affects the production of these molecules
in Tigriopus. We found that the exposure of Tigriopus to actinic light significantly
increased the production of astaxanthin (0.65 mg g-1 of dry biomass) and total fatty
acids (2.786 μg g-1 of dry biomass). On the other hand, moderate temperatures (21 °C)
favoured the production of these molecules.
This study suggests that T. californicus can produce a series of high-value molecules
from more common molecules, making this species of zooplankton a promising
candidate for producing krill-like oil, rich in EPA and DHA and with higher
concentrations of astaxanthin. These results warrant further research to investigate the
adaptation of T. californicus to mass production in the reactor developed in the LEAF
project
Destination Management: The Influence of Local Food
Get PDFThis study investigates tourist attitudes to local food on destination choice, travel motivation, satisfaction and perceived object-related and existential authenticity. Additionally, the mediating effects of authenticity on these relationships is also examined. A quantitative survey (n = 368) by questionnaire was conducted. Data was analysed using factor analysis and Structural Equation Modelling (SEM) to show that tourist attitudes to local food influence destination choice, satisfaction and perceptions of object-related and existential authenticity. Furthermore, it was found that existential authenticity, rather than object-related authenticity had a greater impact on the relationships between tourist attitudes to local food and destination choice, travel motivation and satisfaction. A clear and influential relationship between tourists’ attitudes to local food and travel behaviour was found. Tourists want an existential authentic local food experience where they can be actively involved. Destinations should emphasise unique regional specialities and highlight the experiential value of local food
BIOTRANSFORMATIONS EMPLOYING NITRILE HYDROLYSING ENZYMES TOWARDS THE ENANTIOSELECTIVE SYNTHESIS OF β-AMINO ACIDS
Get PDFNitrile hydrolysing enzymes continue to be of great interest particularly for their pharmaceutical applications. This work set out to utilise novel bacterial isolates containing nitrile-metabolising enzyme systems in the synthesis of a series of chiral β-amino acids and amines with key goals to achieve high enantioselectivity and reaction efficiency. Biocatalysis offers many advantages as an alternative to traditional chemical synthetic methods employed in the production of fine chemicals such as pharmaceuticals with improved productivity, higher yields, shortened synthetic sequences, and reduced costs. In addition, the use of biocatalysts in synthesis adheres to many of the “green chemistry principles” which have become core values of pharmaceutical production.
Initial work focussed on further assessing the functional group tolerance and mechanistic action of bacterial isolate SET1 with a view to the production of β-amino acids. A series of model β-aminonitriles, structurally related to the β-hydroxynitriles previously studied were synthesised and evaluated. Whilst the synthesis of the aliphatic unprotected nitrile, 3-aminobutyronitrile, was unsuccessful and led to its purchase, the remaining seven nitriles were successfully synthesised. The corresponding acid and amide standards were also synthesised. Additionally, work was carried out to develop analytical methods to assess yield and purity of the reaction products. Some of this work entailed derivatisation of the products to allow for successful analysis. Bacterial isolate SET1 unfortunately has shown to be disappointingly poor at selectively hydrolysing the unprotected β-amino nitriles, 3-aminobutyronitrile and 3-amino-3-phenylpropionitrile. The acid yields were extremely low, with the highest being <1% at pH 7 and steadily decreased as pH increased. The ee results again were very low, with the highest ee being 29% at pH 7 and this steeply dropped again as pH increased, and by pH 9 the ee was 5%. Studies on protected variants of 3-aminobutyronitrile gave more promising results, in particular with the N-Benzyl group which gave the overall best result of acid product with 75% ee and 6% yield.
Screening was carried out on five bacterial isolates from the PMBRC bank to identify possible other isolates to work with. They were screened on 3-aminobutyronitrile and 3-phenyl-3-propionitrile at pH 7 and 9. The best results were seen from bacterial isolates 6 and 39. Both isolates 6 and 39 gave excellent ee’s of 99% at pH 9 and ee’s of 89% and 87% respectively at pH 7. For 3-phenyl-3-propionitrile, isolate 39 was the only one to show activity giving an ee of >99% at pH 7 with no activity at pH 9. Bacterial isolate 39 was thus selected for further investigations and to screen it against the N-protected amino nitriles.
Contamination was unfortunately discovered with isolates 6 and 39, and this placed on hold further work with these isolates. A novel nitrilase enzyme Nit1, was then acquired from the PMBRC isolate bank. Nit1 showed improved results with 3-ABN from the initial screen with 76% yield and 24 % (S) ee being observed. As for the N-protected variants, it only showed activity with the benzyl aliphatic nitrile. It encouragingly achieved ee’s of 43% (S) at pH 7 and 4% (S) at pH 9 for this substrate. Some issues were experienced however with the presence of solvent and buffer from the biotransformations, possibly interfering with the HPLC results and extensive method development had to be carried. More robust HPLC methods were successfully developed which allowed for high throughput screening and would enable future work to be carried out with Nit1 more efficiently
An exploratory study of how lessors in the Irish aircraft leasing sector engage with corporate social responsibility
Get PDFThis Doctorate of Business Administration (DBA) thesis explores how and why lessors in the Irish aircraft leasing sector engage with corporate social responsibility (CSR) and the internal processes in place to put CSR activities into practice. To address this aim, the research objectives are as follows: 1. To carry out a CSR review of the websites of the top 50 lessors based in Ireland. 2. To understand how and why Irish leasing companies are engaging with CSR. 3. To identify what internal processes are employed by lessors in the Irish aircraft leasing sector to support such CSR engagement. 4. To understand why are such internal processes chosen by lessors. The study uses theories as lenses through which to view the uses legitimacy, stakeholder and institutional theory as the lenses to understand how and why lessors engage with CSR and the internal processes in place to support such activities. The research design employed is qualitative which firstly consisted of a field familiarisation involving a website review of the CSR disclosures of the top 50 lessors based in Ireland. The field familiarisation which influenced the sample selection was followed by 19 semi-structured interviews with senior management from a sample across the top 50 lessors in the Irish aircraft leasing sector. It was identified that lessors contribute to CSR in a wide variety of ways with the benefactors typically having charitable status and specialising in the areas of children’s health and education. There was evidence that the environmental threat and diversity & inclusion were emerging areas of CSR activity, however there appears to be a lack of real policy and activity actually being undertaken by lessors. It was also found that lessors are motivated to engage with CSR activity to retain and recruit staff, to self-protect against adverse government regulation and give back to the leasing sector. From a contribution to knowledge perspective the findings show a variation across leasing companies in terms of CSR processes which allows a framework to be prepared which sets out the three stages of CSR processes and the characteristics of firms within each stage. The study also builds on prior research and provides new insights into internal CSR processes. The study also finds that while all leasing firms are legitimising to some extent, the level of legitimacy varies depending on what stage of the CSR framework lessors fall within. From a contribution to practice perspective the research results in a CSR practical tool which will aide lessors when implementing CSR processes and provides guidance for companies when transitioning through the different stages of the CSR framework
Hydrogel-based Bio-nanomachine Transmitters for Bacterial Molecular Communications
No full textBacterial quorum sensing can be engineered with a view to the design of biotechnological applications based on their intrinsic role as a means of communication. We propose the creation of a positive feedback loop that will promote the emission of a superfolded green fluorescence protein from a bacterial population that will flow through hydrogel, which is used to encapsulate the cells. These engineered cells are heretofore referred to as bio-nanomachine transmitters and we show that for lower values of diffusion coefficient, a higher molecular output signal power can be produced, which supports the use of engineered bacteria contained within hydrogels for molecular communications systems. In addition, our wet lab results show the propagation of the molecular output signal, proving the feasibility of engineering a positive feedback loop to create a bio-nanomachine transmitter that can be used for biosensing applications
EMI Handbook : Tertiary level teachers' handbook developed by Erasmus+ TAEC Project
Get PDFThis document contains English-Medium Instruction teacher training materials from the TAEC project. The project is co-funded by the Erasmus+ programme of the European Union
Distributed Denial of Service Cyberbioattack Affecting Bacteria-based Biosensing Systems
Get PDFBacteria are microorganisms found in the human body, and almost in everywhere, that recently they have been investigated as human gut’s health indicator. After colonizing a surface, bacterial populations form biofilms, which is their natural protection mechanism against physical attacks, harmful chemical compounds and environmental changes. Recent studies have shown that bacteria can be engineered to act as biosensors and bioactuators, externally controlled by electric signals. Despite the benefits provided by biosensors in terms of metabolic diseases diagnosis and treatment, they also open the door to novel cyberbioattacks due to the impossibility of implementing security mechanisms in resource-constrained engineered bacteria. In this context, we have reproduced a distributed denial of service (DDoS) cyberbioattack performed by engineered bacteria that diffuse jamming signals affecting the production of the biofilm structure. A pool of experiments has shown that higher amplitudes and periods in the signal controlling the engineered bacteria have a greater impact on the biofilm disruption
Shop Floor Employees Engagement with Organisational Performance Measurement and Management Systems within the Printing Sector
No full textMany organisations invest considerable time and resource in their performance measurement and management systems (PMM) as a means to inform employees of business performance and to generate ways and means to improve performance. Where these systems are effective positive outcomes can accrue. At a time when the print industry, the site of this study, faces many challenges, observational evidence suggests that from a practical sense, shop floor employees engagement with their organisations PMM system may not be as strong as it could in these enterprises. This Doctorate in Business Administration (DBA) study seeks to explore this issue with the primary objective being to establish if and how shop floor employees engage with the PMM system. The research method employed is an exploratory qualitative study within an interpretivist tradition. The strategy of inquiry is case study based and the primary data collection techniques used are threefold, semi-structured interviews, documentation review and observational techniques. NVivo software is used to analyse the data and help with the interpretation of findings. The study comprehensively reviews the extant literature in the areas of, performance measurement and management and employee engagement. Key findings that emanated from the research were that shop floor employees had little or no engagement with their organisations PMM system in a practical sense. The PMM system itself contributed considerably to the extent of employee disengagement found. From a theoretical perspective, the key contribution to engagement theory stems from there being a number of antecedents identified, more salient than others, as being the main factors in employee disengagement with the PMM system. These are: feedback, organisational justice, autonomy, reward and recognition, opportunities for development, leader – member exchange, social support, workplace climate and dispositions. In addition, a number of new antecedents have been identified, being, the PMM system, craft person pride and the double engagement gap. Finally, a theoretically based framework was developed to inform the print sector and sectors with similar features of the key factors that contribute to the extent of disengagement found. Stemming from this, recommendations are provided that are of relevance to organisations (within and beyond the sector) who are experiencing disengagement with their PMM systems from shop floor employees
An investigation of the economic potential of Short Rotation Forestry in Ireland
Get PDFAn increase in Short Rotation Forestry (SRF) in Ireland is expected in response to the increasing demand for fibre products and wood energy. SRF is the practice of cultivating fast growing tree species mainly for the production of biomass, through a rotation length of less than 20 years in Ireland. Although forest policy is promoting SRF, currently establishment is limited. This thesis aims to investigate the potential financial value of practicing SRF and evaluate whether SRF should be financially managed to allocate a range of assortments to diverse markets or supply a single market only. The work included: 1) Quantification of above ground biomass by dry matter content, merchantable volume and energy content from four SRF stands, two of Eucalyptus spp. and two of Populus spp.; 2) A market survey identifying pallet producers and the wood energy sector as most willing to use SRF material; 3) Benchmarking conditions that facilitated market development in Oregon with current conditions in Ireland, identifying: large scale plantations; high value product market development; and, investment in research, education and marketing, as key conditions; 4) Development of a unit conversion tool to quantify and value wood resources by volume, weight and energy parameters for market segment comparison and 5) Determination, from the landowner’s perspective, of the optimal financial value of SRF and finding maximum returns were for eucalyptus stands used for diverse markets, mainly small sawlog for pallet production. Contrary to policy objectives, SRF will not contribute significant biomass to fibre and fuel markets, under current financial and market conditions. Policy promoting SRF must be long term, and supported by industry, research and education to gain landowners acceptance. Further research on SRF wood properties and yield models will be necessary to underpin SRF development in Ireland
