The objective of this study is to explore the effect and mechanism of ultrasound on chitin extraction from shrimp shells powder (SSP) by the co-fermentation of Bacillus subtilis and Acetobacter pasteurianus. After pre-treating the SSP with high-intensity ultrasound (HIU) at 800 W, the protease activity in the fermentation solution reached 96.9 U/mL on day 3, which was significantly higher than for SSP that had not been pre-treated with ultrasound (81.8 U/mL). The fermentation time of the chitin extraction process was 5.0 d without ultrasound pre-treatment, while it was shortened to 4.5 d when using ultrasound at 800 W to treat SSP. However, there were no obvious differences when we applied ultrasound at low power (200 W, 400 W). Furthermore, chitin purified from shrimp shells pre-treated with HIU at 800 W exhibited lower molecular weight (11.2 kDa), higher chitin purity (89.8%), and a higher degree of deacetylation (21.1%) compared to SSP with no ultrasound pre-treatment (13.5 kDa, 86.6%, 18.5%). Results indicate that HIU peels off the protein/CaCO₃ matrix that covers the SSP surface. About 9.1% of protein and 4.7% of Ca²⁺ were released from SSP pre-treated with HIU at 800 W. These figures were both higher than with no ultrasound pre-treatment (4.5%, 3.2%). Additionally, the amount of soluble protein extracted from SSP through HIU at 800 W was 50% higher than for the control sample. SDS-PAGE analysis indicated that the soluble protein was degraded to the micromolecule. It also revealed that HIU (600, 800 W) induced the secondary and tertiary structure destruction of protein extracted from SSP. In conclusion, HIU-induced degradation and structural damage of protein enhances the protein/CaCO₃ matrix to be peeled off from SSP. Also, in the co-fermentation process, an increase of protease activity further accelerates deproteinization.

本研究旨在探讨超声波对枯草芽孢杆菌和巴氏醋杆菌共同发酵从虾壳粉（SSP）中提取甲壳素的效果及其机制。. 在800 W高强度超声（HIU）预处理SSP后，发酵液中的蛋白酶活性在第3天达到96.9 U/mL，显着高于未经超声预处理的SSP (81.8 单位/毫升)。甲壳素提取工艺发酵时间为5.0 d，无超声预处理，而800 W超声处理SSP发酵时间缩短至4.5 d。然而，当我们以低功率（200 W、400 W）应用超声波时，没有明显的差异。此外，与未经超声预处理的 SSP 相比，用 800 W HIU 预处理从虾壳中纯化的几丁质表现出较低的分子量 (11.2 kDa)、较高的几丁质纯度 (89.8%) 和较高的脱乙酰度 (21.1%)。处理 (13.5 kDa, 86.6%, 18.5%)。结果表明HIU剥离了蛋白质/CaCO₃覆盖 SSP 表面的矩阵。约 9.1% 的蛋白质和 4.7% 的 Ca ²⁺从用 HIU 在 800 W 预处理的 SSP 中释放。这些数字均高于未进行超声预处理的情况 (4.5%, 3.2%)。此外，通过 HIU 在 800 W 从 SSP 中提取的可溶性蛋白质的量比对照样品高 50%。SDS-PAGE分析表明可溶性蛋白质被降解为小分子。它还揭示了 HIU (600, 800 W) 诱导了从 SSP 中提取的蛋白质的二级和三级结构破坏。总之，HIU诱导的蛋白质降解和结构损伤增强了蛋白质/CaCO ₃要从 SSP 中剥离的矩阵。此外，在共发酵过程中，蛋白酶活性的增加进一步加速了脱蛋白。