Engineering topics

Bruckbauer, Aaron

Publications and source records attributed to Bruckbauer, Aaron.

3 records

DOE OSTI2024

Engineering the Novel Extremophile Alga Chlamydomonas pacifica for High Lipid and High Starch Production as a Path to Developing Commercially Relevant Strains

Microalgae offer a compelling platform for the production of commodity products, due to their superior photosynthetic efficiency, adaptability to nonarable lands and nonpotable water, and their capacity to produce a versatile array of bioproducts, including biofuels and biomaterials. However, the scalability of microalgae as a bioresource has been hindered by challenges such as costly biomass production related to vulnerability to pond crashes during large-scale cultivation. This study presents a pipeline for the genetic engineering and pilot-scale production of biodiesel and thermoplastic polyurethane precursors in the extremophile species Chlamydomonas pacifica. This extremophile microalga exhibits exceptional resilience to high pH (>11.5), high salinity (up to 2% NaCl), and elevated temperatures (up to 42 °C). Initially, we evolved this strain to also have a high tolerance to high light intensity (>2000 μE/m 2 /s) through mutagenesis, breeding, and selection. We subsequently genetically engineered C. pacifica to significantly enhance lipid production by 28% and starch accumulation by 27%, all without affecting its growth rate. We demonstrated the scalability of these engineered strains by cultivating them in pilot-scale raceway ponds and converting the resulting biomass into biodiesel and thermoplastic polyurethanes. This study showcases the complete cycle of transforming a newly discovered species into a commercially relevant commodity production strain. This research underscores the potential of extremophile algae, including C. pacifica, as a key species for the burgeoning sustainable bioeconomy, offering a viable path forward in mitigating environmental challenges and supporting global bioproduct demands.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2024

Renewable and Biodegradable Polyurethane Foams with Aliphatic Diisocyanates

The transition to renewable plastics will require the development of substitutes with existing industrial standards and manufacturing processes. Polyurethanes (PU), versatile plastics, are traditionally dominated by aromatic diisocyanates, which are challenging to derive from renewable sources. However, for higher biocontent, it is crucial to utilize aliphatic diisocyanates, which can be sourced from renewable plant or algae waste streams. Historically, PU foams relied on aromatic diisocyanates for essential hard segments, resulting in desired physical properties. Here, we report the generation of high-performance renewable and biodegradable PU foams utilizing aliphatic diisocyanates and aromatic polyols, translating hard segments into the polyester polyol component using biosourced furan dicarboxylic acid (FDCA) monomers. We demonstrate that an FDCA-based PU is suitable for foams with performance characteristics that meet commercial tolerances and can biodegrade under backyard compost conditions. Here, this demonstrates steps toward redesigning traditional petrochemical-based polymers to accommodate new biological monomers.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Sustainable production of plastic degrading enzymes

The 21st century faces the challenge of transitioning to a climate-neutral economy. This hurdle will need to be addressed in a myriad of approaches, including all societal spheres, as highlighted in several UN and EU reports, including new and accessed technologies. Among them, biotechnology can play a core role by exploiting its environmental benefits (e.g., substituting fossil-based products and expected greenhouse emission reductions). In some cases, biotech can even outperform fossil counterparts' features (e.g., the biodegradability of some bioplastics). Microalga is an attractive bioplastic feedstock in this scenario since it directly substitutes petroleum and captures CO2. However, albeit its environmental benefits, the microalgal process still needs to be tipped economically and the net-positive ecological impact improved to drive adoption. To that end, we envisioned the use of a green alga as a source of bioplastic feedstock and industrial enzymes, combining natural traits of microalgae with engineered properties in a resourceful process to petroleum-based products replacement. As proof of concept, we demonstrated that we could use C. reinhardtii, a green algae, to produce plastic-degrading enzymes. We assemble a vector to secrete PHL7, a recently described PETase, capable of degrading post-consumer PET plastic. We successfully engineered the cell line to secrete the plastic-degrading enzyme. We confirmed the secretion of the enzyme by observing halos in agar plates supplemented with plastic dispersions, enzymatic assays, zymograms, and protein sequencing of supernatant samples. This approach allows using green algae to replace petrochemical-derived plastic while producing the tool necessary to recycle existing plastics sustainably.

Dutra Molino, Joao Vitor↗