Synthetic biology in polyextremophilic algae and co culture for food waste revalorization
Abstract
Biotechnology with microbes has far-reaching human value, however, modern fermentation is inherently inefficient, where half the carbon substrates are lost through respiration. Photosynthetic algae can use the nitrogen, phosphorous and carbon from urban, agricultural, and industrial waste-streams as substrates to build their biomass that is rich in protein, oils, starch, and specialty chemicals like pigments or sterols and yield clean, discharge suitable, water. An underexplored characteristic of algae in biotechnology ismixotrophy, the simultaneous consumption of organic carbon while conducting photosynthetic carbon fixation, a process which can enable >90% carbon conversion to biomass. Mixotrophy can be achieved with heterotrophic-phototrophic strain mixtures in co-culture thatconduct gas exchange with oneanother, opening the possibility of efficient carbon conversion to products. Cyanidiophyceae are polyextremophilic red algae from acidic hotsprings. Two genera have gained notoriety: Cyanidioschyzon merolae (strain 10D) and Galdieria sulphuraria. Both are amenable to cultivation in extreme conditions of 42-60 #C and pH 0.5-2 minimizing their contamination by otherorganisms and contain higher protein than and similar amino acid contents to animal meat. G. sulphuraria can consume >50 other organic carbon sources for growth, C. merolae only CO2. Transformation of C. merolae has recently been de-risked in our hands which now enables broad possibilities of its genetic engineering. It ispossible to co-culture (engineered) C. merolae and G. sulphuraria, wherein G. sulphuraria consumes organic carbon, producing CO2 which is then consumed by C. merolae which in turn provides O2 to G. sulphuraria. Combining respiration and photosynthetic gas exchange enables bioconversion of organic substrates to biomass. We will focus on use of the excrement of soldier-fly larvae as the nutrient source for this cultivation # as this one of the best means of food-waste revalorization. Soldier fly larvae can turn complex food wastes, like that generated by cafeterias, into high protein larvae, CO2, and ammonia-rich excrement. The Cyanidiophyceae thrive in high ammonia and CO2 conditions, which would be detrimental to most other algae. This project will explore metabolic engineering in C. merolae and its co-culture with G.sulphuraria on waste-stream inputs. The goal is to generate two biomasses # C. merolae with engineered co-products and G. sulphuraria with its native protein contents. C. merolae lacks a cell wall, making it readily lysable in comparison to G. sulphuraria, a structural difference that will enable ease of downstream processing. Collectively, we will enhance our understanding of the possibilities of genetic engineering in C.merolae, while simultaneously showing a means to revalorize otherwise wasted resources into high-protein high-value algal bioproducts.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 14, 2024
- Source ID
- N629092512005
Entities
People
- Kyle Lauersen
Organizations
- King Abdullah University of Science and Technology
- Office of Naval Research
- United States Navy