This study aims to assess whether ultra-high-molecular-weight polyethylene (UHMWPE) fibers can be successfully embedded in a polylactic acid (PLA) matrix in a material extrusion 3D printing (ME3DP) process, despite the apparent thermal incompatibility between the two materials. The work started with assessing the maximum PLA extrusion temperatures at which UHMWPE fibers withstand the 3D printing process without melting or severe degradation. After testing various fiber orientations and extrusion temperatures, it has been found that the maximum extrusion temperature depends on fiber orientation relative to extrusion pathing and varies between 175 °C and 185 °C at an ambient temperature of 25 °C. Multiple specimens with embedded strands of UHMWPE fibers have been 3D printed and following tensile strength tests on the fabricated specimens, it has been found that adding even a small number of fiber strands laid in the same direction as the load increased tensile strength by 12% to 23% depending on the raster angle, even when taking into account the decrease in tensile strength due to reduced performance of the PLA substrate caused by lower extrusion temperatures.

3D printed specimens (ASTM D638 Type I) were manufactured from ABS and ASA material via additive manufacturing through material extrusion 3D printing (ME3DP). During manufacturing, the printing process has been paused, pre-impregnated biaxial or uniaxial glass fiber mesh has been placed onto the ABS/ASA substrate and then the printing process has been resumed. The obtained composite specimens have been subjected to tensile strength testing and results have been compared to those of specimens printed from homogenous material. The influence of raster angle, glass fiber direction and mesh density on resulting toughness has also been analyzed. It was found that inserting uniaxial glass fiber increases toughness of specimens in the axial direction, with a drop in layer adhesion if biaxial fiber is used. Test specimens manufactured with 30 uniaxial fiber strands embedded in a 0o raster angle 3D printed thermoplastic matrix match mechanical characteristics of injection-molded parts. The maximum mesh density without leading to delamination is one layer of glass fiber every two layers of thermoplastic matrix.

The following study reports on the first thraustochytrid isolates identified from Iceland. They were collected from three different locations off the northern coast of the country (Location A, Skagaströnd; Location B, Hveravík; and Location C, Eyjafjörður). Using 18S rDNA sequence analysis, isolates from Locations A and B were identified within the Thraustochytrium kinnei species while other isolates within the Sicyoidochytrium minutum species when compared to other known strains. Cells isolated from Locations A ( $2.10\pm 0.70$ g/L) and B ( $1.54\pm 0.17$ g/L) produced more biomass than the ones isolated from Location C ( $0.43\pm 0.02$ g/L). This study offers the first-time examination of the utility of byproducts from fisheries as a nitrogen source in media formulation for thraustochytrids. Experiments showed that isolates produced more biomass (per unit of substrate) when cultured on nitrogen of marine ( $2.55\pm 0.74$ g/L) as compared to of commercial origin ( $1.06\pm 0.57$ g/L). Glycerol ( $2.43\pm 0.56$ g/L) was a better carbon source than glucose ( $1.84\pm 0.57$ g/L) in growth studies. Fatty acid (FA) profiles showed that the isolates from Location C (S. minutum) had low ratios of monounsaturated ( $4.21\pm 2.96\%$ ) and omega-6 ( $0.68\pm 0.59\%$ ) FAs. However, the isolates also had high ratios of docosahexaenoic acid (DHA; $35.65\pm 1.73\%$ ) and total omega-3 FAs ( $40.39\pm 2.39\%$ ), indicating that they could serve as a source of marine oils for human consumption and in aquaculture feeds. The T. kinnei isolates from Location A could be used in biodiesel production due to their high ratios of monounsaturated ( $18.38\pm 6.27\%$ ) long chain ( $57.43\pm 8.27\%$ ) FAs.