Comparative Analysis of Composition and Porosity of the Biogenic Powder Obtained from Wasted Crustacean Exoskeletonsafter Carotenoids Extraction for the Blue Bioeconomy

Abstract

The recovery and recycling of wasted resources are at the forefront of contemporary global issues. Methods of addressing several different issues may go hand-in-hand with each other, such as linking food waste recycling into bio-based adsorbent materials and wastewater treatment. Crustacean exoskeletons are promising candidates for bio-friendly adsorbents; however, maximizing their efficiency requires the optimization of processing technology. Crustacean meat offers an (often luxury) culinary delicacy, while their waste exoskeletons offer opportunities for smart recycling of the magnesian calcite nanoporous biocomposite. Here, we conduct a structural characterization of the exoskeletons of three crustacean species to assess how the extraction of valuable carotenoids affects prospects for the further valorization of their porous powder. The exoskeleton powder’s composition and morphology were investigated by SEM, Raman spectroscopy, FTIR and XRD. The biomineral component magnesian calcite was recorded both in native and in post-extraction exoskeleton powder. Acetone extraction, however, partially removed organic matter from the exoskeletons, resulting in the porosity of the respective powder increasing significantly from below 10 m2 g−1 in the native powder to over 32 m2 g−1 in post-extraction samples of blue crab and spider crab exoskeletons—while the spiny lobster exoskeleton exhibited low porosity, as measured by the BET method. This new insight could improve exoskeleton processing in the sustainable circular economy and applied blue bioeconomy—most notably for adsorbent materials for pollutants dissolved in water or as ordered, nature-derived nanostructured templates.

Comparative Screening Study on the Adsorption of Aqueous Pb(II) Using Different Metabolically Inhibited Bacterial Cultures from Industry

“…This demonstrated that the metabolically inactive SS, C1, C2, Cons, PB, and KP surfaces contained active functional groups. To determine the identities of active organic species, the region between 1400 and 1700 cm −1 was deconvoluted as per Nekvapil et al [58], as shown below in Table 4. In the KP microbial strain, the hydroxyl functional group was revealed due to the occurrence of the broad peak found at a wavenumber 3298 cm −1 [67].…”

A Novel Nanoporous Adsorbent for Pesticides Obtained from Biogenic Calcium Carbonate Derived from Waste Crab Shells

“…Shells of the Atlantic blue crab (Callinectes sapidus) were gathered during regular environmental monitoring activities in the eastern Adriatic Sea (Croatia). The soft tissue was mechanically removed from the shells, carotenoids extracted, and micropowder produced according to the method recently described in detail by Nekvapil et al [15].…”

“…These are the intermediate blue crab shell products immediately after the 500 • C treatment and before the NaOH wash, termed BC-500, and the finalized adsorbent after the 700 • C treatment and HCl wash, termed BC1. Specific surface area, pore volume, and their size distribution were measured using the procedure from Nekvapil et al [15] via nitrogen sorption at 77 K using a Sorptomatic 1990 device (Thermo Electron, Waltham, MA, USA). Pre-treatment of the adsorbent precursor and the adsorbent at the final stage comprised degassing at 150 • C under vacuum for 4 h. The specific surface area was estimated according to the standard BET procedure (0.01-0.2 p/p 0 ), while the total pore volume was estimated using the Dollimore-Heal method for the desorption branch.…”

“…The pore surface area of these shells can be readily measured in native samples via nitrogen physisorption. It ranges from 7.17 to 11.05 m 2 g −1 depending on the species [13][14][15]. This is in contrast with the fibrous and flexible exoskeletons of shrimps and lobsters, which, despite having a brittle and fibrous texture [12,16], are not suitable for BET measurement.…”

“…This testifies to the capacity of shell micropores and canals to house dissolved substances which remain within the bulk material after drying. Nekvapil et al [15] have further shown that shell pore surface area and pore volume can be significantly increased through technically simple treatments, such as acetone immersion. It creates synergy between adsorbent material production and carotenoids extraction via a blue biotechnology approach within the overall context of works on the food waste management issue.…”