Circular Economy

Circular Economy.

Real-time monitoring of healthy omega-3 production in microalgae

A viability study

EPA and DHA. are essential fatty acids that humans need to live. Currently, they are usually obtained through fish oil, either from supplement or directly from oily fish. Unfortunately, fish farming is not sustainable and there is gathering interest in sourcing fatty acids from algae cells. The problem with algae growth comes from the varying lipid production per batch. Mid-production analysis is done on freeze dried samples after some time has passed, and fatty acid content cannot be measured until after the batch is complete. A real-time, on-line monitoring tool would greatly aid in algae production. Seven analytical techniques have been compared with Raman spectroscopy chosen as the most viable option to monitor omega-3 production in micro-algae.

New Challenger for Sustainable Ethanol Production in Industrial Biorefineries


Nations urgently need to tackle climate change in harmony with a circular economy to accomplish Sustainable Development Goals. Using sustainable biomass for sustainable industrial ethanol production seems attractive. Recently, the outstanding features of the arid plants nopales, aka prickly pear cactus, became headlines. Nopales outcompete algae and other biomasses in many aspects. Nopales are resilient, and climate change sparked their advancing invasion across European countries and other places.

Poster prickly pear cactus ethanol LCA
Poster presented at 7th Green and Sustainable Chemistry Conference, Dresden, Germany.

A sustainable biorefinery for ethanol production from nopales could holistically support promising outlooks on energy transition, water positive activities and food security near cities. However, the environmental impact and energy efficiency of this novel biorefinery for renewable energy under realistic scenarios is unknown. Traditional chemical pretreatments are polluters that can improve through environmental assessment and bio/chemical process design.  

We conducted experiments and assessments of scenarios for cleaner ethanol production from nopales in a biorefinery.  Four scenarios considered two fertilisers, two pretreatments and two operational modes. We conducted life cycle assessment, energy balances and energy efficiency calculations. The most polluting scenario uses fossil fertilisers, acid hydrolysis and neutralization of nopal nutrients, and it resulted in approximately four times the global warming potential of the best scenario.  Organic fertilisers and the use and reuse of ionic liquids with acetone for washing was the most ecofriendly scenario.

We propose a cleaner design showing the lowest impacts in all categories, including Global Warming, Acidification and Eutrophication Potentials and more. Besides, the design used the lowest amount of energy per unit of energy as ethanol fuel. It also has the best energy efficiency since it converted three-fold the amount of spent energy, in the worst scenario, into net energy as ethanol fuel.

Sustainable biorefineries and sustainable biomasses are opportunities in the circular economy while pursuing climate risk mitigation, carbon neutrality and green energy for sustainable development.