Microalgal Biotechnology

We study biomass productivity and biomass biorefiniery towards biofuels, feed and biomaterials, concertedly whith microalgae-based CO₂ capture and waste-water reclamation for alternative and sustainable industrial processes. Some of our studies addressed the possibility of converting the biomass of N₂-fixing cyanobacteria into biomass of selected eukaryotic microalgae wich accumulate large amounts of carbohydrates or lipids as feedstocks for biofuels. By optimization of biomass downstream processes towards bioethanol production, we showed the incorporation into a biomass productive platform of P recycled from food waste (bone meal) for an overall production of feed and fuel from CO₂, N₂ and recycled P. The platform is felxible enogh to recycle these nutirnts internally to produce algal biomass or an algae-based plant crop fertilizer and soil conditioner.

Recently we proposed a semi-empirical model of potential algal biomass and oil productivity in the suthamerican continent by simulated-climate cultivation.

Biotechnology of biological N₂-fixation

Our research focus is to increase the use of biological N₂-fixation in sustainable agriculture to help alleviating dependance on expensive synthetic N-fertilizers towards food security in less developed regions and to improve environmantal performance of agriculture in heavily industrialized areas. We define and pursue near, middle and long-term goals for thses developments which are based on the production of organic N-fertilizers from biomass of N₂-fixing cyaobacteria; metabolic engineering to enhance crop N-fertilizing properties of bacterial inoculants; and direct transfer of bacterial nitrogen fixation genes into plant organelles, respectively. More recently, we stared a new line of research which involves studies on the N₂-fixing cyanobionts of diatoms to better undestand its regulation in the context of an Eukaryotic metabolism, and as a presumptive model of an evolutionary snap shot towars the outcome of a “N₂-fixing organelle”.

Assessment of alternative models to aid tailoring nitrogen fixation engineering into plant organelles

• Genetic improvement of ammonium release by diazotrophic bacteria and fertilization of plants
• Nuclear transformation of the microalga Chlamydomonas reinhardtii and targeting of Nif proteins into mitochondria or chloroplast
• Genetic transformation and Nif proteins targeting into mitochondria of hairy roots of common bean and carrot
• Transient expression of Nif proteins in Nicotina bentamiana leaves
• Stable expression of Nif proteins in Arabidopsis thaliana plants
• Optimization of hydroponic method to produce hundreds of grams of thaliana roots
• Purification of NifH expressed in thaliana

Dynamics and regulation of nif gene expression unveiled in diatom spheroid bodies

• Isolation and cultivation of diatom species bearing nitrogen-fixing cyanobacterial endosymbionts called spheroid bodies
• Analysis of Nif proteins expression in spheroid bodies
• Genome project of Ephitemia proboscidea and its spheroid bodies

Bioprospecting for fungal enzymes for applications in microalgal biomass biorefineries

Appl Microbiol Biotechnol., 107; pp.591–607
2022  |  Journal article
DOI: 10.1007/s00253-022-12328-9
CONTRIBUTORS: Bader A.N., Sanchez Rizza L., Consolo V.F., Curatti L.

Promises and challenges for expanding the use of N2-fixing cyanobacteria as a fertilizer for sustainable agriculture

Cyanobacterial Lifestyle and its Applications in Biotechnology, 2022, 5:99-158
2022  |  Book Chapter
DOI: 10.1016/B978-0-323-90634-0.00002-0
CONTRIBUTORS: Ambrosio R., Sanchez Rizza L., Do Nascimento M., Pacheco Jimenez H.G., Miranda Ramos L.M., Hernandez J.A., Curatti L.

Deferred control of ammonium cross-feeding in a N₂-fixing bacterium-microalga artificial consortium

Appl Microbiol Biotechnol., 105; pp.2937–2950
2021  |  Journal article
DOI: 10.1007/s00253-021-11210-4
CONTRIBUTORS: Ambrosio R., Curatti L.