Microalgal biomass as a fermentation feedstock for bioethanol production

BACKGROUND The increasing cost of fossil fuels as well as the escalating social and industrial awareness of the environmental impacts associated with the use of fossil fuels has created the need for more sustainable fuel options. Bioethanol, produced from renewable biomass such as sugar and starch materials, is believed to be one of these options, and it is currently being harnessed extensively. However, the utilization of sugar and starch materials as feedstocks for bioethanol production creates a major competition with the food market in terms of land for cultivation, and this makes bioethanol from these sources economically less attractive. RESULT This study explores the suitability of microalgae (Chlorococum sp.) as a substrate for bioethanol production via yeast (Saccharomycesbayanus)under different fermentation conditions. Results show a maximum ethanol concentration of 3.83 g L -1 obtained from 10 g L-1 of lipid-extracted microalgae debris. CONCLUSION This productivity level (∼38% w/w), which is in keeping with that of current production systems endorses microalgae as a promising substrate for bioethanol production.

Dewatering of microalgal culture for biodiesel production : exploring polymer flocculation and tangential flow filtration

Background: Conventional biodiesel production relies on trans-esterification of lipids extracted from vegetable crops. However, the use of valuable vegetable food stocks as raw material for biodiesel production makes it an unfeasibly expensive process. Used cooking oil is a finite resource and requires extra downstream processing, which affects the amount of biodiesel that can be produced and the economics of the process. Lipids extracted from microalgae are considered an alternative raw material for biodiesel production. This is primarily due to the fast growth rate of these species in a simple aquaculture environment. However, the dilute nature of microalgae culture puts a huge economic burden on the dewatering process especially on an industrial scale. This current study explores the performance and economic viability of chemical flocculation and tangential flow filtration (TFF) for the dewatering of Tetraselmis suecicamicroalgae culture. Results: Results show that TFF concentrates the microalgae feedstock up to 148 times by consuming 2.06 kWh m-3 of energy while flocculation consumes 14.81 kWhm-3 to concentrate the microalgae up to 357 times. Economic evaluation demonstrates that even though TFF has higher initial capital investment than polymer flocculation, the payback period for TFF at the upper extreme ofmicroalgae revenue is ∼1.5 years while that of flocculation is ∼3 years. Conclusion: These results illustrate that improved dewatering levels can be achieved more economically by employing TFF. The performances of these two techniques are also compared with other dewatering techniques.

Rapid production of a plasmid DNA encoding a malaria vaccine candidate via amino-functionalized poly(GMA-co-EDMA) monolith

Malaria is a global health problem; an effective vaccine is urgently needed. Due to the relative poverty and lack of infrastructure in malaria endemic areas, DNA-based vaccines that are stable at ambient temperatures and easy to formulate have great potential. While attention has been focused mainly on antigen selection, vector design and efficacy assessment, the development of a rapid and commercially viable process to manufacture DNA is generally overlooked. We report here a continuous purification technique employing an optimized stationary adsorbent to allow high-vaccine recovery, low-processing time, and, hence, high-productivity. A 40.0 mL monolithic stationary phase was synthesized and functionalized with amino groups from 2-Chloro-N,N- diethylethylamine hydrochloride for anion-exchange isolation of a plasmid DNA (pDNA) that encodes a malaria vaccine candidate, VR1020-PyMSP4/5. Physical characterization of the monolithic polymer showed a macroporous material with a modal pore diameter of 750 nm. The final vaccine product isolated after 3 min elution was homogeneous supercoiled plasmid with gDNA, RNA and protein levels in keeping with clinical regulatory standards. Toxicological studies of the pVR1020-PyMSP4/5 showed a minimum endotoxin level of 0.28 EU/m.g pDNA. This cost-effective technique is cGMP compatible and highly scalable for the production of DNA-based vaccines in commercial quantities, when such vaccines prove to be effective against malaria. © 2008 American Institute of Chemical Engineers.

Development of a pilot-scale bacterial fermentation for plasmid-based biopharmaceutical production using a stoichiometric medium

The recognition of the potential efficacy of plasmid DNA (pDNA) molecules as vectors in the treatment and prevention of emerging diseases has birthed the confidence to combat global pandemics. This is due to the close-to-zero safety concern associated with pDNA vectors compared to viral vectors in cell transfection and targeting. Considerable attention has been paid to the potential of pDNA vectors but comparatively less thought has been given to the practical challenges in producing large quantities to meet current rising demands. A pilot-scale fermentation scheme was developed by employing a stoichiometrically-designed growth medium whose exceptional plasmid yield performance was attested in a shake flask environment for pUC19 and pEGFP-N1 transformed into E. coliDH5α and E. coliJM109, respectively. Batch fermentation of E. coliDH5α-pUC19 employing the stoichiometric medium displayed a maximum plasmid volumetric and specific yield of 62.6 mg/L and 17.1 mg/g (mg plasmid/g dry cell weight), respectively. Fed-batch fermentation of E. coliDH5α-pUC19 on a glycerol substrate demonstrated one of the highest ever reported pilot-scale plasmid specific yield of 48.98 mg/g and a volumetric yield of 0.53 g/L. The attainment of high plasmid specific yields constitutes a decrease in plasmid manufacturing cost and enhances the effectiveness of downstream processes by reducing the proportion of intracellular impurities. The effect of step-rise temperature induction was also considered to maximize ColE1-origin plasmid replication.

Enhancing methacrylate-monolith-based downstream processes to champion plasmid DNA production

Increasing numbers of preclinical and clinical studies are utilizing pDNA (plasmid DNA) as the vector. In addition, there has been a growing trend towards larger and larger doses of pDNA utilized in human trials. The growing demand on pDNA manufacture leads to pressure to make more in less time. A key intervention has been the use of monoliths as stationary phases in liquid chromatography. Monolithic stationary phases offer fast separation to pDNA owing to their large pore size, making pDNA in the size range from 100 nm to over 300 nm easily accessible. However, the convective transport mechanism of monoliths does not guarantee plasmid purity. The recovery of pure pDNA hinges on a proper balance in the properties of the adsorbent phase, the mobile phase and the feedstock. The effects of pH and ionic strength of binding buffer, temperature of feedstock, active group density and the pore size of the stationary phase were considered as avenues to improve the recovery and purity of pDNA using a methacrylate-based monolithic adsorbent and Escherichia coli DH5α-pUC19 clarified lysate as feedstock. pDNA recovery was found to be critically dependent on the pH and ionic strength of the mobile phase. Up to a maximum of approx. 92% recovery was obtained under optimum conditions of pH and ionic strength. Increasing the feedstock temperature to 80°C increased the purity of pDNA owing to the extra thermal stability associated with pDNA over contaminants such as proteins. Results from toxicological studies of the plasmid samples using endotoxin standard (E. coli 0.55:B5 lipopolysaccharide) show that endotoxin level decreases with increasing salt concentration. It was obvious that large quantities of pure pDNA can be obtained with minimal extra effort simply by optimizing process parameters and conditions for pDNA purification.

Growth medium selection and its economic impact on plasmid DNA production

Current developments in gene medicine and vaccination studies are utilizing plasmid DNA (pDNA) as the vector. For this reason, there has been an increasing trend towards larger and larger doses of pDNA utilized in human trials: from 100-1000 μg in 2002 to 500-5000 μg in 2005. The increasing demand of pDNA has created the need to revolutionalize current production levels under optimum economy. In this work, different standard media (LB, TB and SOC) for culturing recombinant Escherichia coli DH5α harbouring pUC19 were compared to a medium optimised for pDNA production. Lab scale fermentations using the standard media showed that the highest pDNA volumetric and specific yields were for TB (11.4 μg/ml and 6.3 μg/mg dry cell mass respectively) and the lowest was for LB (2.8 μg/ml and 3.3 μg/mg dry cell mass respectively). A fourth medium, PDMR, designed by modifying a stoichiometrically-formulated medium with an optimised carbon source concentration and carbon to nitrogen ratio displayed pDNA volumetric and specific yields of 23.8 μg/ml and 11.2 μg/mg dry cell mass respectively. However, it is the economic advantages of the optimised medium that makes it so attractive. Keeping all variables constant except medium and using LB as a base scenario (100 medium cost [MC] units/mg pDNA), the optimised PDMR medium yielded pDNA at a cost of only 27 MC units/mg pDNA. These results show that greater amounts of pDNA can be obtained more economically with minimal extra effort simply by using a medium optimised for pDNA production.

Process engineering aspects of plasmid-based biopharmaceuticals production : tackling the threatening vaccine shortages to prevent global pandemics

Infectious diseases such as SARS, influenza and bird flu have the potential to cause global pandemics; a key intervention will be vaccination. Hence, it is imperative to have in place the capacity to create vaccines against new diseases in the shortest time possible. In 2004, The Institute of Medicine asserted that the world is tottering on the verge of a colossal influenza outbreak. The institute stated that, inadequate production system for influenza vaccines is a major obstruction in the preparation towards influenza outbreaks. Because of production issues, the vaccine industry is facing financial and technological bottlenecks: In October 2004, the FDA was caught off guard by the shortage of flu vaccine, caused by a contamination in a US-based plant (Chiron Corporation), one of the only two suppliers of US flu vaccine. Due to difficulties in production and long processing times, the bulk of the world's vaccine production comes from very small number of companies compared to the number of companies producing drugs. Conventional vaccines are made of attenuated or modified forms of viruses. Relatively high and continuous doses are administered when a non-viable vaccine is used and the overall protective immunity obtained is ephemeral. The safety concerns of viral vaccines have propelled interest in creating a viable replacement that would be more effective and safer to use.

Performing Rural Masculinities : A Case Study of Diggers and Dealers

This chapter examines what Parpart and Zalewski (2008) label 'the man question' in terms of the rural. That is, 'how masculinity comes to be "made" as a continuing process within the social context' of rural places and spaces (Kerfoot and Knights 1993: 662). Our understanding of masculinities as discursively produced, relational, multiple and changing is given empirical force through a case study of the annual resource conference, Diggers and Dealers. The conference, held in the remote mining town of Kalgoorlie in Western Australia since 1992, is today the largest international meeting for the resource sector, attracting over 2000 attendees. Through an analysis of 120 texts related to the conference from 2006 to the present, including media repotis, blogs and conference programs and speeches, we demonstrate how, what is essentially a corporate event, is imported into the rural and constructed through the intersecting discourses of rurality, masculinity and heterosexuality. That is, though the first such meeting may have taken place spontaneously in Kalgoorlie, the delegates, and the 'skimpy' barmaids who serve patrons in their underwear or sometimes topless and are seen as central to the event, are flown into town for the conference. Kalgoorlie, as a working mining community on the edge of the deseti, provides both spectacle and conditions for the enactment of frontier masculinity not possible in the metropole.

Endotoxin removal : a critical step in vaccine production

A major drawback to the immunological potency of conventional vaccines, resulting in reduced level of immune responses, tissue injury, shock and high cytotoxicity, thus making their applications contraindicated in immunodeficiency diseases, is the presence of high contaminant concentrations in vaccine titers. Vaccine contamination arises from the simultaneous occurrence of competitive pathways resulting in the formation of other bio-products during cellular metabolism aside the pathways necessary for the production of vaccine molecules. One of such vaccine contaminating molecules is endotoxins which are mainly lipopolysaccharides (LPS) complexes found in the membrane of bacterial cell wall. The structural dynamics of these molecules make their removal from vaccine titers problematic, thus making vaccine endotoxin removal a major research endeavour. This presentation will discuss a novel technique for reducing the endotoxin level of vaccines. The technique commences with the disentanglement of endotoxin-vaccine molecular bonding and then capturing the vaccine molecules on an affinity monolith to separate the vaccine molecules from the endotoxins.

Dancing as Knowledge Production/Dancer as Researcher in Practice-led Research

This chapter discusses research undertaken for a PhD in dance, highlighting the oscillating and ambivalent nature of practice-led research methods. Holding an unusual position within the field of practice-led research in dance, the researcher adopted the role of dancer within four creative processes led by four choreographers. Although instigating and leading this research, the author produced new knowledge of dancing practices whilst being directed creatively by the choreographers in the research environment. In line with many definitions of practice-led research, the methods used were emergent from the research arena and responsive to the requirements of the project. Deeply imbricated in the research environment, the researcher used her embodied self as a research tool, as the one who participated, discovered and recorded. This outsider/insider role of researcher/participant produced a series of meta-positions, leading to a mixed-modal outcome that encompassed live performance, a movement treatise and a written thesis.

Children’s physical activity, health and physical education in isolated rural contexts : the views of parent educators in Queensland

This paper describes the views of parent educators of their children’s levels and types of physical activity. The study was conducted at two mini-schools in western Queensland. These are occasion where students who undertake formal education through various Schools Distance Education, come together for a week of educational activity. Parents (mostly mothers) were interviewed using a semi-structured approach. The interview data were then analysed for dominant themes using a constant comparison method. The emergent themes related to nutrition and physical activity. Within the physical activity theme, notions of the great outdoors, work and organised sport skill development also emerged.

An investigation of early career teachers’ perceptions of professional development opportunities and career advancement for teachers in rural and remote Queensland

It is generally accepted that to live and work in the remote regions of Australia requires specific skills and expertise to accommodate the shifting demands of outback life. For professionals assigned to such areas by employing bodies, this is particularly the case, and teachers are no exception. In addition to such personal attributes, professionals such as teachers must maintain currency in their professional practice both to serve their students appropriately and to ensure that they become eligible for future promotions and transfers possibilities. This study investigated whether teachers in rural and remote regions are disadvantaged in ways that could potentially affect their teaching careers in negative ways, in particular in terms of professional development and career advancement opportunities. Such opportunities are crucial if teachers are to provide an education of high relevance to rural and remote children who are already considered to be significantly disadvantaged in terms of educational provision. The data are presented in the form of a single teacher narrative, a composite tale aimed at telling the story of rural and remote teachers, professional development provision and career advancement opportunities. It was apparent that teachers in these contexts face serious challenges in terms of their professional and career development.

Bio-hydrogen production from food waste through anaerobic fermentation

In order to protect our planet and ourselves from the adverse effects of excessive CO2 emissions and to prevent an imminent non-renewable fossil fuel shortage and energy crisis, there is a need to transform our current ‘fossil fuel dependent’ energy systems to new, clean, renewable energy sources. The world has recognized hydrogen as an energy carrier that complies with all the environmental quality and energy security, demands. This research aimed at producing hydrogen through anaerobic fermentation, using food waste as the substrate. Four food waste substrates were used: Rice, fish, vegetable and their mixture. Bio-hydrogen production was performed in lab scale reactors, using 250 mL serum bottles. The food waste was first mixed with the anaerobic sewage sludge and incubated at 37°C for 31 days (acclimatization). The anaerobic sewage sludge was then heat treated at 80°C for 15 min. The experiment was conducted at an initial pH of 5.5 and temperatures of 27, 35 and 55°C. The maximum cumulative hydrogen produced by rice, fish, vegetable and mixed food waste substrates were highest at 37°C (Rice =26.97±0.76 mL, fish = 89.70±1.25 mL, vegetable = 42.00±1.76 mL, mixed = 108.90±1.42 mL). A comparative study of acclimatized (the different food waste substrates were mixed with anaerobic sewage sludge and incubated at 37°C for 31days) and non-acclimatized food waste substrate (food waste that was not incubated with anaerobic sewage sludge) showed that acclimatized food waste substrate enhanced bio-hydrogen production by 90 - 100%.