Green processes and products

The focus of this area of research is to explore the production of natural materials that are useful and in particular, relevant to biomedical and health related applications. The processes used should be environmentally friendly in terms of CO₂ emission, carbon utilization and subsequent separation and purification processing steps. Our main focuses are bacterial cellulose, a nanobiomaterial, produced by microbial fermentation and the use of microalgae/cyanobacteria in photochemical processes utilizing CO₂ as the carbon source to produce algal oil for biofuels, natural and degradable polymers and astaxanthin, a potent natural antioxidant that is a FDA approved dietary ingredient.

Bacterial cellulose

Bacterial cellulose (BC) is a polysaccharide polymer that can be produced in appreciable quantity extracellularly by certain bacteria. BC is unique in morphology and properties and distinguishes itself from the conventional cellulose produced from plants / trees. This creates opportunities for applications that are not possible for plant derived cellulose. It is a nanobiomaterial. It has a fiber diameter of ~15 nm. It can absorb water >10,000 times of its mass. BC is produced in a high degree of purity that requires minimum purification processing. This potentially can reduce the removal removal of trees from forests and reduce emissions from the conventional pulping processes. BC can be functionalized for various applications (e.g. therapeutic delivery, medical devices) and converted into cellulose nanocrystals (CNC) for high value applications (e.g. biomedical devices)

Photosynthetic organisms for Biofuels, biopolymers, health related molecules

Assembly of useful molecules from CO₂ is one of the simplest and energy efficient synthesis process. It also has the side benefit of reducing CO₂ emission. The principal organisms under investigation are: Chlorella kessleri, Nannochloropsis oculata, Spirulina platensis,and Haematococcus pluvialis.

Magnetic stimulation enhances microalgae growth

Periodic exposure of Chlorella kessleri to static magnetic fields enhances microalgal biomass production. The growth rate is maximal at a field strength of 10 mT. Net photosynthetic capacity and respiratory rate also increases. This NPC enhancement after the removal of magnetic field decays in a first-order mode with a half-life of 3.3 days. Cellular biochemical composition (antioxidants) is magnetic field strength dependent. This effect is also observed on other microalgae and can be applied for biomass yield enhancement and maximization of certain biochemical components that are targeted for production.

Algal oil for biofuels

Nannochloropsis oculata is a marine microalga commonly used in aquaculture. This species has shown promise in biofuels application since it has high lipid content and does not require the use of potable water to grow. A static magnetic field is used to stimulate its growth and increase in lipid accumulation.

Biopolymers [Poly(hydroxybutyrate)] produced directly from CO₂

Cyanobacterium Spirulina (Arthrospira) platensis, a commercially feasible blue-green alga, is able to synthesize poly(3-hydroxybutyrate) (PHB), a biodegradable and biocompatible polymer, as an energy storage product of photosynthesis directly from CO₂ at a higher solar energy conversion efficiency compared to PHB production by microbial fermentation. A new LED photobioreactor has been designed and build for Spirulina platensiscultivation. PHB of high purity is extracted from Spirulina with a degree of crystallinity lower than that of commercial PHB. Improved polymer properties, such as reduced brittleness due to a lower crystallinity, could further increase the range of applications of PHB, especially in the medical device area.

Astaxanthin

Astaxanthin is a potent, natural antioxidant. It is an FDA approved dietary ingredient. Common sources include microalgae, salmon, krill and shrimp. Using the microalga Haematococcus pluvialis and in the presence of a static magnetic field, biomass produced was maximized at a field strength of 10mT with concomitant enhancement of astaxanthin yield.