Cerruti Marta, Kim Jeong-Hoon, Pabst Martin, Van Loosdrecht Mark C M, Weissbrodt David G
Department of Biotechnology, Delft University of Technology, Delft, Netherlands.
Front Microbiol. 2022 Oct 19;13:1014695. doi: 10.3389/fmicb.2022.1014695. eCollection 2022.
Purple bacteria (PPB), anoxygenic photoorganoheterotrophic organisms with a hyper-versatile metabolism and high biomass yields over substrate, are promising candidates for the recovery of nutrient resources from wastewater. Infrared light is a pivotal parameter to control and design PPB-based resource recovery. However, the effects of light intensities on the physiology and selection of PPB in mixed cultures have not been studied to date. Here, we examined the effect of infrared irradiance on PPB physiology, enrichment, and growth over a large range of irradiance (0 to 350 W m) in an anaerobic mixed-culture sequencing batch photobioreactor. We developed an empirical mathematical model that suggests higher PPB growth rates as response to higher irradiance. Moreover, PPB adapted to light intensity by modulating the abundances of their phototrophic complexes. The obtained results provide an in-depth phylogenetic and metabolic insight the impact of irradiance on PPB. Our findings deliver the fundamental information for guiding the design of light-driven, anaerobic mixed-culture PPB processes for wastewater treatment and bioproduct valorization.
紫色细菌（PPB）是一类不产氧的光合有机异养生物，具有高度多样的代谢方式，在底物上能产生高生物量，是从废水中回收营养资源的有潜力的候选者。红外光是控制和设计基于PPB的资源回收的关键参数。然而，迄今为止尚未研究光照强度对混合培养中PPB生理特性和选择的影响。在此，我们在厌氧混合培养序批式光生物反应器中，研究了大范围光照强度（0至350 W m）下红外辐照度对PPB生理特性、富集和生长的影响。我们建立了一个经验数学模型，该模型表明随着光照强度增加，PPB生长速率更高。此外，PPB通过调节其光合复合体的丰度来适应光照强度。所获得的结果提供了关于辐照度对PPB影响的深入系统发育和代谢见解。我们的研究结果为指导用于废水处理和生物产品增值的光驱动厌氧混合培养PPB工艺设计提供了基础信息。
