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

污水污泥的大量产生及其在环境中的安全处理是一个世界性难题。我们研究的长期目标是生产聚羟基烷酸酯（PHA）或生物塑料，利用污泥作为微生物来源或作为原料和废物作为额外的碳源。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，以提高微生物的生长和PHA生产能力。本工艺还侧重于开发一种新型、高效、环保的PHA提取和净化工艺，利用纯培养从废水污泥中获得PHA。对连续离心机的工艺参数进行优化，使PHA回收率最大化。PHA提取过程中产生的废液（剩余生物质、洗涤水和含蛋白废水）的回用，确定了环保型PHA生产工艺的发展。此外，从废液中回收蛋白质可以使PHA生产过程更加经济。该研究将由两名博士生和一名兼职技术人员进行。本研究的成功完成：1)将为制浆造纸公司的含油废弃物提供一条新的利用途径，将使从发酵污泥中开发一种具有成本效益的PHA提取工艺，并将开发一种从PHA提取过程中产生的废物流中回收蛋白质的新工艺；2)该工艺的开发还将提高PHA的产量和生产速度；3)减少60- 70% w/w的污泥量，从而最大限度地降低处置成本；4)通过减少需要在环境中处理的残余污泥，最大限度地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环保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.