Abstract:

The goals of this article are in memory of Professor Daniel I.C. Wang's contribution to biorefining, the interaction and motivation between Professor Wang and me in this area, and I present opinions on addressing several key challenges of the next-generation biorefinery. Prof. Wang was the primary driver of innovation in both education and multidisciplinary research initiatives that have defined modern Biochemical Engineering, a frontier of chemical engineering. To meet great needs, he adjusted his scientific research directions timely throughout his career from microbial fermentation, single cell protein production, animal cell cultures to biorefineries. The industrial processes of the first-generation biorefinery plants based on food resources (e.g., corn kernel, sucrose, aged grains, used oil) have been very mature, but they potentially have negative impacts on food security and the environment, resulting in their limited development. Due to current low prices of crude oil, the second-generation biorefineries based on non-food lignocellulosic biomass are suffering from relatively high production cost, leading to their economic inviability. New biorefineries, which could be distinctive from the second generation biorefineries that produce liquid biofuels as dominant products, would convert lignocellulosic feedstock (e.g., rice straw, corn stover, energy crops) to multiple products, such as food and feed, healthy sweeteners, and other biocommodities (e.g., biofuels and biomaterials). New biorefineries could be implemented with newly-developed biochemical engineering tools, such as consolidated bioprocessing, novel enzymes, metabolic engineering, in vitro synthetic biology (i.e., multiple-enzyme molecular machines that assemble a number of natural enzymes, novel-function or engineered enzymes, coenzymes, and/or biomimetic coenzymes to form artificial pathways to implement novel biomanufacturing capacity beyond the limits of microbial fermentation and cell cultures). They could be industrial scalability, economic viability, and environmental sustainability. Also, agricultural revolution would take place by the cultivation of perennial plants in marginal lands to replace annual crops, wherein perennial plant communities have higher biomass yield per hectare with less resource management, store more carbon, maintain better water quality, utilize fertilizers more efficiently, tolerate extreme weather, and resist pests. The combination of the cultivation of nonfood perennial (energy) crops and next-generation biorefineries could address major social and economic needs of China, such as food supply, energy security, general health, and environmental conservation. Also, new biorefineries and new agricultural revolution could address challenge of our time to meet increasing need in the energy-food-water nexus without compromising the benefit of next generations.

Key words: agricultural revolution, biorefinering, biochemical engineering, biomanufacturing, food security, multiple-enzyme molecular machine, enzyme engineering, in vitro synthetic biology

摘要：

本文目的是回忆王义翘（Daniel I. C. Wang）教授对生物炼制领域的贡献，以及作者与王教授在该领域的交往、互动和激励，并且作者针对生物炼制领域几个问题提出个人观点。王教授大力地推动多学科交叉的研究创新，使生化工程正式发展成为化学工程的一个前沿分支。为面向重大需求，王教授一生中多次调整他的科研方向。基于粮食原料的第一代生物炼制工厂生产工艺已经十分成熟，但对粮食安全和环境有着负面影响，发展受限。因为当前石油价格下行，基于非粮生物质的第二代生物炼制工厂受到预处理和纤维素酶成本的限制，举步维艰，在经济上暂时还缺乏可行性。未来的新生物炼制工厂能够将非粮生物质（如秸秆）有效地转化为多个产品，如粮食和饲料、健康糖以及众多大宗生物产品（如燃料和材料）。多种新生化工程工具的发展和使用将有助于新生物精炼厂的实现，例如整合生物加工、新酶发现和利用、体外合成生物学（如多酶分子机器）、基因工程、合成生物学等。未来的新生物精炼厂将具有工业可放大性、经济可盈利性和环境可持续性的性质。种植多年生的非粮作物和未来生物炼制工厂相结合，将有可能帮助解决中国社会经济发展所面临的重大需求，如粮食安全、能源安全、大健康以及环境保护等。

关键词: 农业革命, 生物炼制, 生化工程, 生物制造, 粮食安全, 多酶分子机器, 酶工程, 体外合成生物学