Production of bioplastics using pulp and paper mill activated sludge (PPMAS) as a raw material and new sludge isolated microorganisms

废水污泥产生量大，其在环境中的安全处置是世界性难题。我们研究的长期目标是以废水污泥为原料生产附加值适销对路的产品。另一方面，由于与传统塑料相关的环境问题、减少温室气体(GHG)的必要性以及政府为尽量减少合成塑料的使用而制定的措施，对生物塑料或多羟基烷酸酯(PHA)的需求大幅增加。因此，本研究的主要目标是开发一种以制浆造纸厂活性污泥(PPMAS)和其他废物为原料生产生物塑料的经济工艺。事实上，我们已经获得了一个污泥微生物联盟，它积累了高达70%w/w的PHA。本研究项目的具体目标包括从该联盟中分离和鉴定单个高活性菌株，在摇瓶和发酵罐中进行工艺优化研究，以分离的菌株和标准菌株作为对照，以预处理或未经处理的PPMAS为原料，最大限度地提高PHA的产量。PPMAS还将单独进行测试或使用额外的碳源(粗甘油)进行强化，以提高PHA的生产率。这项研究的成功完成将：1)提供一种低成本生物塑料的新工艺；2)将污泥体积减少60%-70%(w/w)，并使用生物柴油生产过程中产生的粗甘油；以及3)通过使用废碳将温室气体的排放量降至最低，否则必须安全处置。此外，这项研究非常及时，将帮助加拿大工业以非常有竞争力的成本开发环境友好、商业可行的PHA，以加强加拿大的经济。3名博士、1名PDF和一名研究助理将接受这一新课题的培训。

Wastewater sludge is produced in large quantity and its safe disposal in the environment is a worldwide problem. The long-term goal of our research is to produce value-added marketable products using wastewater sludge as a raw material. On the other hand, demand for bioplastics or polyhydroxy alkanoates (PHA) has increased significantly due to environmental problems associated with conventional plastics, necessity to reduce greenhouse gases (GHG) and the development of government measures to minimize the use of synthetic plastics. Therefore, the principal objective of the present research is to develop an economical process for bioplastics production using pulp and paper mill activated sludge (PPMAS) and other waste material as raw materials. In fact, we have obtained a consortium of sludge microorganisms, which accumulates PHA up to 70% w/w. The specific objectives of the present research project include isolation and identification of individual highly active strains from the consortium, process optimization studies in shake flasks and fermenters to maximize the PHA production employing the isolated strains and the standard strains as control with pre-treated or non-treated PPMAS as a raw material. The PPMAS will also be tested alone or fortified with extra carbon source (crude glycerol) to increase the PHA productivity. The successful completion of the research will: 1) provide a new process for low cost bioplastics; 2) reduce the sludge volume by 60-70 % w/w and use of crude glycerol produced during biodiesel production; and 3) minimize production of greenhouse gases through use of waste carbon, which otherwise must be disposed safely. Furthermore, this research is very timely and will aid Canadian industry to develop eco-friendly, commercially viable PHA at very competitive cost strengthening Canada's economy. 3 Ph.D, 1 PDF and a research associate will be trained on this new subject.