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Removal of sediment mud of lake and sea bottom and bioconversion to the biodegradable plastic using self-flocculated photosynthetic bacteria

利用自絮凝光合细菌去除湖泊和海底沉积泥并生物转化为可生物降解塑料

基本信息

批准号：
08650953
负责人：
SASAKI Ken
金额：
$ 1.54万
依托单位：
Hiroshima-Denki Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650953/
关键词：
self-flocculation photosynthetic bacteria biodegradable plastic sediment mud PHB Rhodovulum sp.Rhodobacter

项目摘要

Focusing on the purification of sediment mud and bioconversion of mud to biodegradable plastic, firstly, chemical analyses of sediment mud were carried out. Sediment mud was consisted of 5% organic matters and 95% of sea sund and contained large amount of phosphorous compounds, After anaerobic digestion of mud suspension (200 g/l artificial sea wate) at 30 C for 7 days, ca. 2 g/l of acetic acid and Ca. 20 mg/l of phosphate ion was released into the broth. Using this anaerobic digestion liquor, a photosynthetic bacterial cultivation was carried out under anaerobic light condition (10 klux illumination) at 30 C.After 3 days culture, ca. 3 g/l of biomass was produced and almost phosphate was removed. Biomass produced contained 62% (dry basis) of polyhydroxybutyrate (PHB). Thus, the possibility of simultaneous purification of sediment mud and production of PHB was observed.Furthermore, high cell density culture of a newly isolated photosynthetic bacteria, Rhodovulum sp. which had the sel-flocculating ability was carried out using a new single tower bioreactor system to purify the anaerobic digestion liquor under aerobicculture condition eliminating light illumination. By this culture system, maximum biomass concentration attained 42.5 g/l after 750 hour culture with artifitial digestion liquor (acetic acid was a carbon source) and PHB content was ca. 30% even under aerobiccondition. In addition, a computer simulation was carried out using several biochemical engineering constants such as growth yield and some specific consumption rates. As the results, the estimations were in good agreement with the data obtained by experiments.Thus, a new bioreactor system become possible to develop by these investigations using this self-immobilizing photosynthetic bacteria. This indicates the possibility of the purification of sediment mud and simultaneous production of biodegradable plastic from sediment mud.

针对底泥的净化及底泥生物转化为生物降解塑料的研究，首先对底泥进行了化学分析。底泥由5%的有机质和95%的海水组成，并含有大量的磷化合物。2 g/l乙酸和Ca. 20 mg/l的磷酸根离子被释放到肉汤中。使用该厌氧消化液，在厌氧光条件（10 klux光照）下于30 ℃进行光合细菌培养。产生3g/l的生物质，并且几乎去除了磷酸盐。生产的生物质含有62%（干基）的聚羟基丁酸酯（PHB）。在此基础上，利用新型单塔生物反应器系统，在无光照的好氧培养条件下，对一株新分离的具有自适应能力的光合细菌Rhodovulum sp.进行了高密度培养，以净化厌氧消化液。在此培养体系中，以乙酸为碳源，人工消化液培养750小时，菌体最大生物量可达42.5 g/l，其中聚羟基丁酸含量约为100 g/l。30%，即使在有氧条件下。此外，还利用几个生化工程常数，如生长产量和某些特定的消耗率进行了计算机模拟。结果表明，该模型与实验结果吻合较好，为利用该自固定化光合细菌构建新型生物反应器提供了可能。这为底泥的净化和底泥生物降解塑料的生产提供了可能性。