Polyhydroxyalkanoates (Bioplastics) production, extraction and protein recovery using pulp and paper wastewater activated sludge as raw material

废水污泥产生量大，其在环境中的安全处置是一个世界性难题。我们研究的长期目标是使用污泥作为微生物来源或作为原料和废物作为额外碳源来生产聚羟基链烷酸酯（PHA）或生物塑料。该研究的主要目标包括探索含油废物作为碳源，并进一步添加到废水污泥中，以增加微生物的生长和PHA生产能力。该工艺还着重于开发一种新型、高效和环境友好的PHA提取和纯化工艺，以使用纯培养物从废水污泥中获得PHA。还考虑了连续离心机的工艺参数的优化，以最大限度地提高PHA回收过程。在PHA提取过程中产生的废物流（残余生物质、洗涤水和含蛋白质的废水）的再利用促进了环境友好的PHA生产过程的发展。此外，从废物流中回收蛋白质可以使PHA生产过程更经济。该研究将由两名博士进行。学生和一名兼职技术员。该研究的成功完成：1）将提供一种新的途径来利用纸浆和造纸公司的含油废物，将能够开发一种从发酵污泥中提取PHA的成本有效的方法，并且还将开发一种从PHA提取过程中产生的废物流中回收蛋白质的新方法; 2）该方法的开发还将能够提高PHA的产率和速率; 3）减少60- 70%（重量/重量）的污泥处置量，从而最大限度地减少处置成本;以及4）通过减少需要在环境中处置的剩余污泥，减少温室气体的产生。此外，这项研究非常及时，将有助于加拿大工业开发生态友好和商业上可行的生物塑料，从而加强加拿大的经济和环境政策。

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 polyhydroxyalkanoates (PHA) or bioplastics using sludge as a source of microorganisms or as a raw material and waste materials as an extra carbon source. The principal objectives of the research proposed involves exploration of oily waste as a source of carbon and further additions to wastewater sludge to increase the growth and PHA production capacity of microorganisms. This process also focuses on the development of a novel, efficient and environmental friendly PHA extraction and purification process to obtain PHA from wastewater sludge using pure culture. Optimization of process parameters for continuous centrifuge to maximize the PHA recovery process is also considered. The reuse of waste streams (residual biomass, wash water and protein containing waste water) generated during PHA extraction process ascertains the development of environmentally friendly PHA production process. Moreover, recovery of proteins from the waste stream could make the PHA production process more economical. The research will be conducted by two Ph.D. students and one part-time technician. The successful completion of the research: 1) will provide a new avenue to use oily waste of the pulp and paper company, will enable to develop a cost effective PHA extraction process from the fermented sludge and will also develop a novel process of protein recovery from the waste stream generated during PHA extraction process; 2) The development of the process will also enable to augment the production of PHA yield and rate; 3) reduce the sludge volume by 60-70 % w/w for disposal and hence minimize disposal cost; and 4) minimize the production of greenhouse gases through savings on lesser residual sludge required to be disposed in the environment. Furthermore, this research is very timely and will aid Canadian industry to develop eco-friendly and commercially viable bioplastics and thus strengthening Canada`s economy and environmental policy.