Research Abbas Alloul

Abstract

Purple non-sulfur bacteria (PNSB) show great potential for environmental biotechnology, producing microbial protein, biohydrogen, polyhydroxyalkanoates (PHA), pigments,... Grown photoorganoheterotrophically, the carbon source is typically more reduced than PNSB biomass, which leads to a redox imbalance. To mitigate the excess of electrons, PNSB can exhibit several 'electron sinking' strategies such as CO2 fixation or H2 production. However, the fundamental understanding of the mechanisms they use to adapt to reduced carbon sources is mostly unknown. Redoxome addresses this knowledge gap with the following questions: i) how do PNSB adapt to individual carbon sources of different electron richness and mixtures thereof, and ii) how do the adaptation mechanisms affect their competitiveness when multiple PNSB are competing for the same resource(s)? For the first time, we address the role played by gene duplication, genome plasticity, and metabolic heterogeneity in bacterial cultures. The complementary expertise of UAntwerpen and UMONS will be combined to decipher their adaptive mechanisms at the metabolic, genetic, functional, and ecological levels, studying pure cultures and bacterial consortia. The fundamental knowledge generated in Redoxome will accelerate applied research initiatives based on PNSB for environmental biotechnology applications.

Researcher(s)

• Promoter: Vlaeminck Siegfried
• Co-promoter: Alloul Abbas

Research team(s)

• Biobased sustainability engineering (SUSTAIN)

Project type(s)

• Research Project

Abstract

Microbial protein is an alternative and sustainable protein source in animal feed and human food. Previous research demonstrated excellent replacement potential of less sustainable, conventional protein sources in aquafeeds and human diets. This project addresses engineering and nonengineering challenges to develop and implement novel microbial protein processes and products that are technically and societally viable. For the production of purple bacteria and aerobic heterotrophs, innovative secondary and renewable feedstocks will be considered. Microbial culture control tools and downstream processing innovations will be developed, along with their automation, to optimize the nutritional and functional quality of the biomass. To support decision-making on the implementation of novel 3 protein products and technologies, environmental impacts and social acceptance factors will be determined. The environmental impact of products and processes will be evaluated using life cycle assessment to determine whether they are superior to conventional protein sources. Social scientific inquiries, such as interviews and surveys, will be conducted to elicit acceptance factors of products and technologies.

Researcher(s)

• Promoter: Vlaeminck Siegfried
• Co-promoter: Alloul Abbas
• Co-promoter: Spiller Marc
• Co-promoter: Vandermoere Frederic

Research team(s)

• Biobased sustainability engineering (SUSTAIN)

Project type(s)

• Research Project

Abstract

Ornamental fish is the third and fifth most common group of pets in the United States and the European Union, respectively, with guppy being one of the most popular freshwater tropical fish. This market and associated environmental aspects continue to grow, spurring fish feed suppliers to use novel and ecological ingredients to boost health, fitness and color. Microalgal biomass, astaxanthin and several probiotics such as Pediococcus acidilactici are already available in commercial feed formulations for aquarists. A promising new sustainable ingredient is purple non-sulfur bacteria (PNSB) biomass. Previous research has shown its use as a probiotic and alternative protein source for shrimp and other aquaculture applications. Patents and scientific literature on the implementation of PNSB biomass in ornamental fish feed are limited, except for the research performed by the University of Antwerp. PurpleGuppy aims to further demonstrate and valorize added-value properties of PNSB biomass in ornamental fish feed. Feeding trials with guppies intend to corroborate the health and esthetic benefits of PNSB as a feed ingredient, resulting in feed formulation protocols with an appealing benefit-cost ratio.

Researcher(s)

• Promoter: De Boeck Gudrun
• Co-promoter: Alloul Abbas
• Co-promoter: Vlaeminck Siegfried

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Transforming the agriculture-based food system is urgently needed to sustainably feed the fast-growing world population. Microbial biomass production for human nutrition i.e. microbial protein provides a solution, particularly when produced on renewable H2 and CO2-derived compounds (e.g. CH4, CH3OH, HCOOH). Purple non-sulfur bacteria (PNSB) are nutritionally appealing for photoheterotrophic protein production, as shown in our previous research. Despite being metabolic versatility champions, growth and nutritional quality of PNSB grown for aerobic or phototrophic hydrogen- or methylotrophy remains largely unexplored. PurpleSky's overall objective is to elucidate the use of H2 and C1 compounds for PNSB and steer towards nutritious biomass through a unique genome-scale computational approach. The project will pioneer in isolating new PNSB specialists on H2 and C1 compounds. Known and new strains will be tested in-silico for targeted nutritional quality tuning, based on genome-scale metabolic models and flux balance analyses. This mechanism-driven approach will enable to efficiently select best parameter and strain combinations for experimental validation. Finally, bioreactor proofs of concept for aerobic and phototrophic growth will be set up to explore how feeding strategy and photoperiod shape the nutritional quality. PurpleSky's mechanism-driven approach for nutritious microbial protein production is novel and a vital step forward for land- and fossil-free PNSB production.

Researcher(s)

• Promoter: Vlaeminck Siegfried
• Fellow: Alloul Abbas

Research team(s)

• Biobased sustainability engineering (SUSTAIN)

Project type(s)

• Research Project

Abstract

The increasing global population and living standards necessitate a protein transition for a more sustainable food system. A solution lies in microbial protein, i.e. the use of microbial biomass as alternative protein source for human nutrition. This is particularly sustainable when based on renewable electron and carbon sources that do not require arable land nor fossil fuels. This is enabled by the movements towards green electrification and carbon capture which yield new routes to H2, CO2 and compounds derived from CO2 (e.g. methanol, formic acid, acetic acid). Key challenges are to produce microbial biomass on these compounds that is nutritious and practically usable. In the Air2Protein project, a target-driven approach will be used to select the best strains, metabolisms and cultivation conditions starting from H2, CO2 and/or CO2 derivatives. Herein, not only the protein 3 content is of interest, but also essential amino acids and fatty acids, and vitamins. Furthermore, novel stabilization and other downstream processing methods will be explored. Air2Protein aligns with the sustainable H2 and CO2 based economy, and aims to contribute to novel nutritious and usable protein ingredients for the food industry.

Researcher(s)

• Promoter: Vlaeminck Siegfried
• Co-promoter: Alloul Abbas
• Co-promoter: Spiller Marc

Research team(s)

Project type(s)

• Research Project

Abstract

One of the vital sectors in Asia important for social and economic wellbeing is shrimp production. Roughly 49% of the production is intended for local consumption as food source. This segment in the fish industry has a high economic significance as it contributes to an export value of 13 billion dollars in Asia. In 2010 this sector was shuddered by an outbreak of the early mortality syndrome (EMS) or more technically known as acute hepatopancreatic necrosis disease (AHPND). It affects shrimp postlarvae within 20-30 days causing up to 100% mortality. The social and economic effects of EMS/AHPND were (and still are) devastating: losses of USD 1 billion for whole Asian shrimp culture sector, total drop in export of 13% (between 2012-2013) and loss of Thailand's dominant position as the world's leading shrimp exporter. It has been reported that Vibrio parahaemolyticus belonging to the clade the Harveyi is the causative agent of EMS/AHPND. There is an urgent need for a sustainable strategy to prevent new EMS/AHPND outbreaks, respecting besides profit especially the people and the planet. To date, the main controlling strategy is total disinfection of pond sediment and water. It is shown that this approach actually contributes to the epidemic spread of the EMS/AHPND disease rather than controlling it. This is attributed to the action that total disinfection results in a disturbance of the ecosystem and an increase in nutrient availability, favoring fast-growing microorganisms in recolonizing the environment (such as Vibrio spp.). A sustainable alternative for total disinfection can be microbial management strategies. Shrimps are cultivated in ponds along with a microbial community in the water. This stable community is actually a gatekeeper and prevents the growth of pathogenic species. These systems are already proven to decrease Vibrio levels and animal mortality. In this project we look to purple bacteira as a way to prevent EMS. These bacteria can easily grow on side streams of aquaculture cultivation tanks and can be fed as feed ingredient.

Researcher(s)

• Promoter: Alloul Abbas

Research team(s)

Project type(s)

• Research Project

Abstract

Flanders is a hotspot of nutrients (nitrogen and phosphorus). This is the result of intensive food production, and nutrient losses along this fertilizer to food conversion chain. To recover lost nutrients, conversion into microbial protein (single cell protein) is a sustainably appealing scenario. Purple bacteria represent an interesting, yet underexplored source for microbial protein production and consumption. The potential of purple bacteria is derived from their metabolism as photoheterotrophs. Firstly, they have a near perfect organic carbon immobilization efficiency in comparison with other heterotrophs, decreasing greatly the carbon input needs. Secondly, purple bacteria also have a high growth rate with respect to other phototrophs, leading to a desirable low land usage footprint. Thirdly, their unique potential to grow on infra-red wavelengths allows a selectivity tool during cultivation. The research objective of this project is to acquire insights into the biotechnological production of purple bacteria in open communities on fermented wastewater from the potato processing industry. It is targeted to demonstrate that biomass enriched in purple bacteria can serve as an excellent feed ingredient for aquaculture.

Researcher(s)

• Promoter: Vlaeminck Siegfried
• Fellow: Alloul Abbas

Research team(s)

Project type(s)

• Research Project