Macroalgal biorefinery concepts for the circular bioeconomy: A review on biotechnological developments and future perspectives

The imminent need for transition to a circular bioeconomy, based on the valorisation of renewable biomass feedstocks, will ameliorate global challenges induced by climate change, environmental pollution and population growth. A reduced reliance on depleting fossil fuel resources and ensured production of eco-friendly and cost-effective bioproducts and biofuels, requires the development of sustainable biorefinery processes, with many utilising macroalgae as feedstock, showing promising and viable prospects. Nonetheless, macroalgal biorefinery research is still in its infancy compared to lignocellulosic biorefineries that utilise terrestrial plants. This article presents a review on the latest scientific literature associated with the development and status of macroalgal biorefineries, and how bioproducts generated from these bioprocesses have contributed towards the bioeconomy. The fundamental need to understand how the unique biochemical composition of macroalgae fit within a biorefinery concept are explained, alongside discussion of the novel biotechnologies that have been applied. In order to comprehend the increasing significance of this exciting field, the review will also provide insight, for the first time, on the current global funding and intellectual property landscape related to macroalgae and their implementation across the entire biorefinery concept. Imperative areas for further research and development, to bridge the gap between fundamental bioscience in the laboratory and the successful application of compatible biotechnologies at a commercial scale, to boost the macroalgae industry are also covered

Identification of Bio-oil Compound Utilizing Yeasts Through Phenotypic Microarray Screening

Abstract: Biomass pyrolysis bio-oil contains a plethora of carbon sources with the potential to be utilized by microorganisms and converted into high value products. However, the majority of these compounds are either highly toxic to microorganisms or are not directly utilizable. Hence research is required to develop methods of separating microbe friendly compounds from inhibitory ones, and to also identify novel microorganisms that can utilise the principal carbon sources in pyrolysis bio-oil. This study employed a phenotypic microarray (PM) technique that measured yeast metabolic output to screen for and shortlist yeast strains able to metabolize various bio-oil carbon sources, with a focus on the anhydrosugar levoglucosan. Four strains of yeast (two Pichia spp. and two Kluyveromyces spp.) were shortlisted due to their high metabolic output (between 79.7 and 113.7 redox signal intensity) on levoglucosan from the PM assay. Under anaerobic fermentation conditions the strains were able to uptake levoglucosan (between 79 and 100% uptake efficiency) but not produce bioethanol; yet trace amounts of acetic acid were generated. This study demonstrated the application of applying the PM technique to screen for novel yeast strains with abilities to metabolize compounds present in pyrolysis bio-oil that could lead to the identification of novel levoglucosan utilization pathways. Graphical Abstract: [Figure not available: see fulltext.]

Optimization of a total acid hydrolysis based protocol for the quantification of carbohydrate in macroalgae

Accurate quantification of carbohydrate content of biomass is crucial for many bio-refining applications. The standardised NREL two stage complete acid hydrolysis protocol was evaluated for its suitability towards seaweeds, as the protocol was originally developed for lignocellulosic feedstocks. The compositional differences between the major polysaccharides in seaweeds and terrestrial plants, and seaweed’s less recalcitrant nature, could suggest the NREL based protocol may be too extreme. Underestimations of carbohydrate content through the degradation of liberated sugars into furan compounds may yield erroneous data. An optimised analysis method for carbohydrate quantification in the brown seaweed L. digitata was thus developed and evaluated. Results from this study revealed stage 1 of the assay was crucial for optimisation however stage 2 proved to be less crucial. The newly optimised protocol for L. digitata yielded 210 mg of carbohydrate per g of biomass compared to a yield of only 166 mg/g from the original NREL protocol. Use of the new protocol on two other species of seaweed also gave consistent results; higher carbohydrate and significantly lower sugar degradation products generation than the original protocol. This study demonstrated the importance of specific individual optimisations of the protocol for accurate sugar quantification, particularly for different species of seawee

High-pressure technology for Sargassum spp biomass pretreatment and fractionation in the third generation of bioethanol production

Sargassum spp is an invasive macroalgae and an alternative feedstock for bioethanol production. Sargassum spp biomass was subjected to high-pressure technology for biomass fractionation under different operating conditions of temperature and residence time to obtain glucan enriched pretreated solids (32.22 g/100 g of raw material). Enzyme hydrolysis process at high pretreated solid loading (13%, w/v) and enzyme loading of 10 FPU/g of glucan was performed, obtaining 43.01 g/L of glucose corresponding to a conversion yield of 92.12%. Finally, a pre-simultaneous saccharification and fermentation strategy (PSSF) was performed to produce bioethanol. This operational strategy produced 45.66 g/L of glucose in the pre-saccharification stage, and 18.14 g/L of bioethanol was produced with a glucose to bioethanol conversion yield of 76.23%. The development of this process highlights the feasibility of bioethanol production from macroalgal biomass in the biorefinery concept

2,3-Dihydroxyisovalerate production by Klebsiella pneumoniae

2,3-Dihydroxyisovalerate is an intermediate of valine and leucine biosynthesis pathway; however, no natural microorganism has been found yet that can accumulate this compound. Klebsiella pneumoniae is a useful bacterium that can be used as a workhorse for the production of a range of industrially desirable chemicals. Dihydroxy acid dehydratase, encoded by the ilvD gene, catalyzes the reaction of 2-ketoisovalerate formation from 2,3-dihydroxyisovalerate. In this study, an ilvD disrupted strain was constructed which resulted in the inability to synthesize 2-ketoisovalerate, yet accumulate 2,3-dihydroxyisovalerate in its culture broth. 2,3-Butanediol is the main metabolite of K. pneumoniae and its synthesis pathway and the branched-chain amino acid synthesis pathway share the same step of the α-acetolactate synthesis. By knocking out the budA gene, carbon flow into the branched-chain amino acid synthesis pathway was upregulated, which resulted in a distinct increase in 2,3-dihydroxyisovalerate levels. Lactic acid was identified as a by-product of the process and by blocking the lactic acid synthesis pathway, a further increase in 2,3-dihydroxyisovalerate levels was obtained. The culture parameters of 2,3-dihydroxyisovalerate fermentation were optimized, which include acidic pH and medium level oxygen supplementation to favor 2,3-dihydroxyisovalerate synthesis. At optimal conditions (pH 6.5, 400 rpm), 36.5 g/L of 2,3-dihydroxyisovalerate was produced in fed-batch fermentation over 45 h, with a conversion ratio of 0.49 mol/mol glucose. Thus, a biological route of 2,3-dihydroxyisovalerate production with high conversion ratio and final titer was developed, providing a basis for an industrial process.Key Points• A biological route of 2,3-dihydroxyisovalerate production was setup.• Disruption of budA causes 2,3-dihydroxuisovalerate accumulation in K. pneumoniae.• Disruption of ilvD prevents 2,3-dihydroxyisovalerate reuse by the cell.• 36.5 g/L of 2,3-dihydroxyisovalerate was obtained in fed-batch fermentation

Rule-based Word Clustering for Document Metadata Extraction

Text classification is still an important problem for unlabeled text

Generating synthetic task graphs for simulating stream computing systems

Stream-computing is an emerging computational model for performing complex operations on and across multi-source, high-volume data flows. The pool of mature publicly available applications employing this model is fairly small, and therefore the availability of workloads for various types of applications is scarce. Thus, there is a need for synthetic generation of large-scale workloads to drive simulations and estimate the performance of stream-computing applications at scale. We identify the key properties shared by most task graphs of stream-computing applications and use them to extend known random graph generation concepts with stream computing specific features, providing researchers with realistic input stream graphs. Our graph generation techniques serve the purpose of covering a disparity of potential applications and user input. Our first "domain-specific" framework exhibits high user-controlled configurability while the second "application- agnostic" framework focuses solely on emulating the key properties of general stream-computing systems, at the loss of domain-specific fine-tuning. © 2013 Elsevier Inc. All rights reserved

A modified technique of retrograde intubation dacryocystorhinostomy for proximal canalicular obstruction

Nikolaos Trakos, Emmanouil Mavrikakis, Kostas G Boboridis, Marselos Ralidis, George Dimitriadis, Ioannis MavrikakisOculoplastic Service, Metropolitan Hospital, Athens, GreecePurpose: To describe a modification of the retrograde intubation dacryocystorhinostomy (DCR) in patients with proximal canalicular obstruction.Materials and methods: Interventional case report of a 43-year-old female with a nine-month history of left epiphora following a road traffic accident involving the proximal lower canaliculus. An external DCR approach was performed. Following the creation of a lower canalicular pseudopunctum, the O’Donoghue silicone stent was introduced through the common ostium, out through the pseudopunctum of the lower canaliculus, and returned through the punctum of the normal upper canaliculus down through the common ostium into the nose.Results: The patient experienced complete resolution of symptoms and on her last follow-up, two years later, her lower canaliculus was patent to syringing.Conclusion: This modification of the retrograde intubation DCR is an effective technique which decreases the intraoperative time needed to insert the tubes and minimises further trauma to the newly created punctal area.Keywords: retrograde dacryocystorhinostomy, proximal canalicular obstruction, midcanalicular obstruction, conjuctivodacryocystorhinostom

Fundamental Control Algorithms in Mobile Networks

In this work we propose simple and efficient protocols for counting and leader election in mobile networks. For mobile networks with fixed base stations we provide a new and very efficient protocol for counting the number of mobile hosts. The main part of the work concentrates on ad-hoc networks (no fixed subnetwork). We provide a model for these networks and leader election (and a special form of counting) protocols for both named and anonymous mobile hosts. In this work we define two protocol classes, the Non-Compulsoryprotocols, which do not affect the motion of the hosts and the Compulsory, which determine the motion of some or all the hosts. By assuming that the mobile hosts move as if each one is doing a continuous random walk on their allowable space S of motions, and by assuming a universal time, we show that our leader election protocol termi