Harnessing the potential of biocatalytic conversion of renewable biomass into value-added products is still hampered by unfavorable process economics. This has promoted the use of biofilms as an alternative to overcome the limitations of traditional planktonic systems. In this paper, the benefits and challenges of biofilm fermentations are reviewed with a focus on the production of low-value bulk chemicals and fuels from waste biomass.

Our study demonstrates that biofilm fermentations can potentially improve productivities and product yields by increasing biomass retention and allowing for continuous operation at high dilution rates. Furthermore, we show that biofilms can tolerate hazardous environments, which improve the conversion of crude biomass under substrate and product inhibitory conditions. Additionally, we present examples for the improved conversion of pure and crude substrates into bulk chemicals by mixed microbial biofilms, which can benefit from microenvironments in biofilms for synergistic multi-species reactions, and improved resistance to contaminants. Finally, we suggest the use of mathematical models as useful tools to supplement experimental insights related to the effects of physico-chemical and biological phenomena on the process.

Major challenges for biofilm fermentations arise from inconsistent fermentation performance, slow reactor start-up, biofilm carrier costs and carrier clogging, insufficient biofilm monitoring and process control, challenges in reactor sterilization and scale-up, and issues in recovering dilute products. The key to a successful commercialization of the technology is likely going to be an interdisciplinary approach. Crucial research areas might include genetic engineering combined with the development of specialized biofilm reactors, biofilm carrier development, in-situ biofilm monitoring, model-based process control, mixed microbial biofilm technology, development of suitable biofilm reactor scale-up criteria, and in-situ product recovery.

利用可再生生物质的生物催化转化为增值产品的潜力仍然受到不利的工艺经济性的阻碍。这促进了使用生物膜作为克服传统浮游系统局限性的替代方法。本文综述了生物膜发酵的好处和挑战，重点是从废弃生物质中生产低价值的散装化学品和燃料。

我们的研究表明，生物膜发酵可以通过增加生物质保留和允许在高稀释率下连续运行来潜在地提高生产力和产品产量。此外，我们表明生物膜可以耐受危险环境，这提高了底物和产物抑制条件下粗生物质的转化率。此外，我们还提供了通过混合微生物生物膜将纯和粗底物转化为散装化学品的例子，这可以从生物膜中的微环境中受益，用于协同多物种反应，并提高对污染物的抵抗力。最后，我们建议使用数学模型作为有用的工具来补充与物理化学和生物现象对过程的影响相关的实验见解。

生物膜发酵的主要挑战来自发酵性能不一致、反应器启动缓慢、生物膜载体成本和载体堵塞、生物膜监测和过程控制不足、反应器灭菌和放大方面的挑战以及回收稀释产品的问题。该技术成功商业化的关键很可能是一种跨学科的方法。关键研究领域可能包括基因工程与专用生物膜反应器的开发、生物膜载体开发、原位生物膜监测、基于模型的过程控制、混合微生物生物膜技术、开发合适的生物膜反应器放大标准，以及现场产品回收。