The valorization of chitinous biomass from underutilized renewable carbon feedstock offers alternative routes for bioproduct development, reducing our dependence on nonrenewable and nonbiodegradable materials composed of fossil carbon. This work utilizes crustacean waste consisting of inedible shells to isolate chitin and its derivatives, chitin nanocrystals and chitosan, from lobster (Homarus gammarus) and spider crab (Maja squinado) shells. Chitin nanocrystals (ChNCs) with a degree of acetylation >93% and crystallinity >90% were obtained by demineralization, deproteinization and acid-hydrolysis, while chitosan was obtained by chitin deacetylation. Free-standing chitosan/ChNCs films were then fabricated from lobster and spider crab after dissolution and casting using 1.5% v/v formic acid. Lobster-derived materials exhibited a good balance between UV-shielding ability, blocking >96% of UV-C and UV-B, while being transparent at visible wavelengths. Neat chitosan films are semiductile, with elongations at break >13% and Young’s modulus values of 2.3 ± 0.7 and 3.4 ± 1.2 GPa for lobster and spider crab-derived chitosan, respectively. Besides, the incorporation of ChNCs increases the Young’s modulus to 5.5 ± 0.8 GPa at 2 wt % for lobster-derived films. Life cycle assessment (LCA) was conducted to quantify the environmental impact of film production and identify process hotspots for future optimization. A carbon footprint of 79.8 kg CO₂ equiv·kg^–1 is obtained for chitosan/ChNC films processed using a 100% renewable energy mix. Results demonstrate that lobster-derived materials are relevant contenders toward defossilization by developing renewable-carbon containing bioproducts with competitive performance against fossil-based materials due to their optical and mechanical properties, as well as their potential biodegradability.

中文翻译：

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来自龙虾和蜘蛛蟹的壳聚糖-甲壳素纳米晶体薄膜：特性和环境可持续性


来自未充分利用的可再生碳原料的几丁质生物质的增值为生物产品开发提供了替代途径，减少了我们对由化石碳组成的不可再生和不可生物降解材料的依赖。这项工作利用由不可食用的壳组成的甲壳类废物从龙虾 (Homarus gammarus) 和蜘蛛蟹 (Maja squinado) 的壳中分离出甲壳素及其衍生物、甲壳素纳米晶体和壳聚糖。通过脱矿质、脱蛋白、酸水解得到乙酰化度>93%、结晶度>90%的甲壳素纳米晶（ChNCs），甲壳素脱乙酰化得到壳聚糖。然后使用 1.5% v/v 甲酸溶解和浇铸后，用龙虾和蜘蛛蟹制备独立式壳聚糖/ChNC 薄膜。龙虾源材料在紫外线屏蔽能力之间表现出良好的平衡，可阻挡 >96% 的 UV-C 和 UV-B，同时在可见波长下透明。纯壳聚糖薄膜具有半延展性，龙虾和蜘蛛蟹衍生的壳聚糖的断裂伸长率 >13%，杨氏模量值分别为 2.3 ± 0.7 和 3.4 ± 1.2 GPa。此外，ChNCs 的加入将龙虾衍生薄膜的杨氏模量提高到 2 wt% 的 5.5 ± 0.8 GPa。进行生命周期评估（LCA）是为了量化薄膜生产对环境的影响，并确定未来优化的工艺热点。使用 100% 可再生能源混合物加工的壳聚糖/ChNC 薄膜的碳足迹为 79.8 kg CO ₂ 当量·kg ^–1 。 结果表明，龙虾衍生材料是去石化的相关竞争者，通过开发含可再生碳的生物产品，由于其光学和机械性能以及潜在的生物降解性，其性能与化石材料相比具有竞争力。