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CURATOR
A pinboard by
Abdelrahman Zaky

I am an Associate Researcher at the University of Nottingham. I received my B.Sc. and M.Sc. in Cairo University. I conducted my Ph.D. jointly between the University of Nottingham and the University of Huddersfield.

I am interested in industrial biotechnology, scientific publication, and teaching.

PINBOARD SUMMARY

MF is using seawater, marine biomass and marine microorganisms in the fermentation process of IB.

Current fermentation technologies used in Industrial Biotechnology (IB) rely on the use of edible crops and freshwater for the production of bioethanol and many other valuable compounds such as solvents, enzymes and proteins. With an ever-growing population and demand for biofuels and other bio-based produces, there are concerns over the use of the limited freshwater and food crops resources for non-nutritional activities. I am investigating a new fermentation strategy called Maine Fermentation (MF). The main purpose of MF is to introduce an alternative source of water (seawater) and biomass (seaweed) for Industrial Biotechnology (IB) in order to reduce pressure on use of freshwater and arable land, allowing these resources to be dedicated to production of food and feeds. Bioethanol is one of the most import IB products and it can be considered the best replacements for petrol because it is a liquid fuel and it has a positive impact on the environment. Worldwide bioethanol production in 2015 exceeded 97 billion litres/year, contributing approximately 2.4% of the world’s fuel consumption for transportation. However, bioethanol has a very high water consumption index, with an average global water footprint of 2855 L H2O/L EtOH. Therefore, a shift from fossil fuel based economy towards biofuel puts an additional pressure on the limited freshwater resources in many regions of our overpopulated planet. Hence, finding alternative water resources is essential to meet the bioethanol target of 2030 and beyond. The key requirements for marine fermentation include; a) finding a suitable yeast strain that can tolerate the high concentrations of salts that exist in seawater, b) finding an accurate analytical method for monitoring the substrate and product during the fermentation process. In consequence, I have recently devolved Zaky’s method for the efficient isolation and evaluation of marine yeasts. Also, I developed a new HPLC methodology for simultaneously measuring chloride, sugars, organic acids and alcohols in food samples. The method was successfully applied to samples derived from seawater fermentation, as well as many food samples. I investigated bioethanol production using seawater-based media and obtained great results that were presented in several international conferences and now being submitted to a peer-reviewed journals.
For more details on marine fermentation, please visit my RG profile: https://www.researchgate.net/profile/Abdelrahman_Zaky3

9 ITEMS PINNED

Systems Level Analysis of the Yeast Osmo-Stat.

Abstract: Adaptation is an important property of living organisms enabling them to cope with environmental stress and maintaining homeostasis. Adaptation is mediated by signaling pathways responding to different stimuli. Those signaling pathways might communicate in order to orchestrate the cellular response to multiple simultaneous stimuli, a phenomenon called crosstalk. Here, we investigate possible mechanisms of crosstalk between the High Osmolarity Glycerol (HOG) and the Cell Wall Integrity (CWI) pathways in yeast, which mediate adaptation to hyper- and hypo-osmotic challenges, respectively. We combine ensemble modeling with experimental investigations to test in quantitative terms different hypotheses about the crosstalk of the HOG and the CWI pathways. Our analyses indicate that for the conditions studied i) the CWI pathway activation employs an adaptive mechanism with a variable volume-dependent threshold, in contrast to the HOG pathway, whose activation relies on a fixed volume-dependent threshold, ii) there is no or little direct crosstalk between the HOG and CWI pathways, and iii) its mainly the HOG alone mediating adaptation of cellular osmotic pressure for both hyper- as well as hypo-osmotic stress. Thus, by iteratively combining mathematical modeling with experimentation we achieved a better understanding of regulatory mechanisms of yeast osmo-homeostasis and formulated new hypotheses about osmo-sensing.

Pub.: 16 Aug '16, Pinned: 26 Aug '17

The water footprint of sweeteners and bio-ethanol.

Abstract: An increasing demand for food together with a growing demand for energy crops result in an increasing demand for and competition over water. Sugar cane, sugar beet and maize are not only essential food crops, but also important feedstock for bio-ethanol. Crop growth requires water, a scarce resource. This study aims to assess the green, blue and grey water footprint (WF) of sweeteners and bio-ethanol from sugar cane, sugar beet and maize in the main producing countries. The WFs of sweeteners and bio-ethanol are mainly determined by the crop type that is used as a source and by agricultural practise and agro-climatic conditions; process water footprints are relatively small. The weighted global average WF of sugar cane is 209 m(3)/tonne; for sugar beet this is 133 m(3)/tonne and for maize 1222 m(3)/tonne. Large regional differences in WFs indicate that WFs of crops for sweeteners and bio-ethanol can be improved. It is more favourable to use maize as a feedstock for sweeteners or bio-ethanol than sugar beet or sugar cane. The WF of sugar cane contributes to water stress in the Indus and Ganges basins. In the Ukraine, the large grey WF of sugar beet contributes to water pollution. In some western European countries, blue WFs of sugar beet and maize need a large amount of available blue water for agriculture. The allocation of the limited global water resources to bio-energy on a large scale will be at the cost of water allocation to food and nature.

Pub.: 02 Aug '11, Pinned: 26 Aug '17

Assessment of saccharification and fermentation of brown seaweeds to identify the seasonal effect on bioethanol production

Abstract: Brown seaweeds such as the kelps are attractive sources of biomass for bioethanol production, but fully optimised saccharification and fermentation conditions have yet to be established. To address this, various saccharification methods using dilute and concentrated acid and enzymes were trialled on three kelp species, Laminaria digitata, Laminaria hyperborea and Saccharina latissima, collected through a full seasonal cycle. Enzymatic hydrolysates were then fermented using Saccharomyces cerevisiae and Pichia angophorae to identify seasonal variations in ethanol yields. Highest glucose yields were achieved using concentrated acid, followed by enzymatic and dilute acid saccharification, respectively. The effect of seasonality showed that the highest glucose and ethanol yields were from kelps harvested during the autumn months and lowest during winter and spring months. However, the season at which biomass was collected did not have any measurable impact on the method of saccharification. Differences in ethanol yields between seaweed species were found with P. angophorae producing more ethanol from L. digitata and L. hyperborea hydrolysates, whilst S. cerevisiae was better for fermentation of S. latissima hydrolysates. It was observed that ethanol conversion yields with S. cerevisiae were higher than the theoretical maximum based on the yield of glucose identified, suggesting that other sugars in addition to glucose were co-fermented. For glucose liberation from seaweeds, terrestrial-derived cellulose and hemicellulose enzyme blends were suitable, but for liberation of all sugar monomers from seaweed polymers, other hydrolytic enzymes need to be investigated. In addition, fermentative microorganisms that are more tolerant of salinity and polyphenols are still required and ideally, be strains that can be engineered to ferment all carbohydrate sources present in kelps.

Pub.: 03 Feb '16, Pinned: 26 Aug '17

A New Isolation and Evaluation Method for Marine Derived Yeast spp with Potential Applications in Industrial Biotechnology.

Abstract: Yeasts that are present in marine environments have evolved to survive hostile environments, which are characterised by high exogenous salt content, high concentrations of inhibitory compounds and low soluble carbon and nitrogen levels. Therefore, yeasts isolated from marine environments could have interesting characteristics for industrial applications. However, the application of marine yeast in research or industry is currently very limited due to the lack of a suitable isolation method. Current methods for isolation suffer from fungal interference and/or low number of yeast isolates. In this paper, an efficient and non-laborious isolation method has been developed and successfully isolated large numbers of yeasts without bacterial or fungal growth. The new method includes a three-cycle enrichment step followed by isolation step and confirmation step. Using this method, 116 marine yeast strains were isolated from 14 marine samples collected in the UK, Egypt and the USA. These strains were further evaluated for the utilization of fermentable sugars (glucose, xylose, mannitol and galactose) using a phenotypic microarray assay. Seventeen strains with higher sugar utilization capacity than a reference terrestrial yeast Saccharomyces cerevisiae NCYC2592 were selected for identification by sequencing of the ITS and D1/D2 domains. These strains belonged to 6 species: Saccharomyces cerevisiae, Candida tropicalis, Candida viswanathii, Wickerhamomyces anomalus, Candida glabrata and Pichia kudriavzevii. The ability of these strains for improved sugar utilization using seawater-based media was confirmed and therefore, they could potentially be utilized in fermentations using marine biomass in seawater media, particularly for the production of bioethanol and other biochemical products.

Pub.: 21 Jul '16, Pinned: 26 Aug '17

A new HPLC method for simultaneously measuring chloride, sugars, organic acids and alcohols in food samples

Abstract: Publication date: March 2017 Source:Journal of Food Composition and Analysis, Volume 56 Author(s): Abdelrahman Saleh Zaky, Nattha Pensupa, Áurea Andrade-Eiroa, Greg A. Tucker, Chenyu Du This paper introduces an original, rapid, efficient and reliable HPLC method for the accurate and simultaneous quantification (g/L) of chloride in samples containing sugars, organic acids and alcohols. Separation was achieved using a HI-Plex H column at 35°C, with H2SO4 (0.005N) as the mobile phase at a flow rate of 0.4mL/min. The column effluent was monitored by a Refractive Index (RI) detector. A linear response was achieved over NaCl concentrations of 0.25–2.5g/L and 5–40g/L. The analytical method inter- and intra-run accuracy and precision were better than ±10.0%. Investigating the mechanism of detection using different chloride and sodium s reviled that this method can be used for determining the total concentration of chloride salts when in suspension. This method was successfully applied to 15 samples of commercial food products and the salt content obtained from this method was compared with 3 other methods for salt determination. The (HI-Plex H) column was designed for determining the concentrations of sugars, organic acids and alcohols when in solution. Hence, application of our new methodology would allow the determination of sugars, alcohols and organic acids in samples derived from seawater-based fermentation media as well as samples from salty food and dairy products.

Pub.: 15 Dec '16, Pinned: 26 Aug '17