High stability in filtration apparatus of African shrimp

Influence of chitin purity on its dissolution behaviour in alkaline solvent

The biopolymer chitin is a promising ingredient for bioplastics due to its strength and stability. Chitin fibres must be isolated from biomass by stripping away tightly bound minerals, proteins, and pigments. Depending on the desired chitin purity, this isolation process can be long and cost-prohibitive on industrial scale. Following isolation, chitin fibres must be dissolved or separated which is challenging due to chitins recalcitrance. Cryo-assisted dissolution in potassium hydroxide has been identified as a fast and non-toxic approach. However, to date, this method has not received widespread attention and has not been evaluated for chitins from different species. The present study demonstrated the dissolution of Northern pink shrimp (P. borealis) chitin using KOH solvent and the influence of residual impurities on dissolution behaviour was investigated for the first time. Three chitin samples with purities ranging from 84 to 97 % w/w were compared, and results confirmed that chitin with lower purity can be successfully dissolved in KOH solvent, provided that minerals were removed prior to dissolution. However, dissolution behaviour and physical properties were strikingly different between the samples. Microscopic analysis of chitin particles allowed the differentiation between exoskeleton features and the identification of insoluble particles, providing potential new avenues to improve dissolution processes.

Specialized spatially-arranged non-circular fibers enhance filtration performance of African shrimp (Atya gabonensis)

African shrimp (Atya gabonensis) inhabit clear freshwaters, where the notably low concentration of food may pose a challenge to the efficacy of filter fibers on the chela for filter-feeding. Here, we investigate how the distinctive cross-sectional characteristics and spatial arrangement of the African shrimp's non-circular fibers contribute to the enhanced filtration performance of these specialized fibers. The unilateral thickening of the wall along the long axis of the elliptical cross-section of African shrimp fibers markedly enhances the filtration performance. The staggered and twisted arrangement of the fibers optimizes the surrounding flow field, achieving a favorable balance between pressure drop and collection efficiency, consequently improving their filtration performance in collecting fine particles (diameter: 2-10μm). Moreover, the arrangement of the fibers substantially increases the effective flow-facing filtering area of the fiber bundles, thus facilitating their efficiency in collecting larger particles (diameter > 10μm). The unique fiber properties of the African shrimp offer novel insights for the design and optimization of new fiber-filtering robots, presenting a wide range of potential applications, such as marine in-situ resource extraction, medical filtration, and industrial filtration.