Conversion of waste fish meat to bio-degradable plastics poly lactic acid by sub-critcal water oxidation

研究了以鱼骨、鱼头、鱼肉和鱼内脏为原料，采用亚临界水解法生产各种有机物的方法。确定了各产物的最佳反应条件。研究了离子交换树脂(DIAION WA30和高孔壳聚糖树脂)对有机酸的吸附平衡和传质性能。通过对废弃鱼肉、内脏和鱼骨的转化研究，得到以下重要结果：(1)在473K下反应5min，从100吨鱼骨、0.64吨磷酸、0.44吨乳酸中提取出25吨鱼骨、1.7吨焦谷氨酸、0.8吨丙氨酸、0.8吨甘氨酸、0.5吨半胱氨酸和1.8吨油。从100吨鱼头中得到1.5吨骨头，0.23吨焦谷氨酸，0.07吨磷酸，4.9吨油，0.2吨脂肪。(2)油中含有昂贵的不饱和脂肪酸，如DHA和EPA。(3)由于最佳反应温度取决于产品类型，(4)乳酸在DIAION WA30离子交换剂上的吸附等温线和壳聚糖珠的吸附等温线均符合Langmuir方程。(5)乳酸在颗粒内的扩散由固相扩散和大孔扩散平行传递解释。由于壳聚糖珠的吸附速率远大于DIAION WA30，因此壳聚糖珠更有利于有机酸的分离。

Production of various organic substances from fish bone, fish head, fish meat and fish entrails by sub-critical water hydrolysis was studied. Optimal reaction was determined for each product. Adsorption equilibrium and mass transfer of organic acid in ion exchange resins (DIAION WA30 and highly porous chitosan resin) were also studied. The following significant results were obtained from the research on conversion of waste fish meat, entrails, and bones.(1) From 100 ton fish bone, 0.64 ton of phosphoric acid, 0.44 ton of lactic acid was extracted by 5 min reaction at 473 K.Then, 25 ton of bone, 1.7 ton of pyroglutamic acid, 0.8 ton of alanine, 0.8 ton of glycine, 0.5 ton of cystine, and 1.8 ton of oil were obtained by sub-critical water hydrolysis at 543 K for 20 min. From 100 ton of fish head, 1.5 ton of bone, 0.23 ton of pyroglutamic acid, 0.07 ton of phosphoric acid, 4.9 ton of oil, and 0.2 ton of fat were obtained.(2) Oil contained valuable and expensive unsaturated fatty acids such as DHA and EPA.(3) Since optimal reaction temperature depends on the type of products, an integrated process which produce different product successively at different reaction temperature can be established.(4) Adsorption isotherm of lactic acid for DIAION WA30 ion exchanger and that for chitosan bead were well explained by Langmuir equation.(5) Intra-particle diffusion of lactic acid was explained parallel transport by solid-phase and macropore diffusion. Since adsorption rate of the chitosan bead was much larger than that of the DIAION WA30, the chitosan bead was favorable for separation of organic acids.