Realizing Strength-Controllable and Selective Bactericidal Valorization of Hydrothermal Liquefaction Wastewater from Biowaste by Temperature and Feedstock Regulation

Hydrothermal liquefaction can convert biowaste into biocrude oil, and its wastewater byproduct (HTL-WP) has been confirmed with a wide antimicrobial spectrum. Here, we engineered strength-controllable and selective bactericides from HTL-WP via regulation of feedstock and operational temperature. Results showed that HTL-WP from different feedstocks exhibited significantly selective inhibition on Escherichia coli and Staphylococcus aureus. Increasing operational temperature showed varied effects on antibacterial strength of HTL-WP from feedstocks with different components. Thereby, HTL feedstocks and temperatures can be used as switches to prepare strength-controllable and selective HTL-WPs, showing significantly selective inhibition on S. aureus with a maximum inhibition zone of 12.08 mm. Meanwhile, we conducted interaction analysis of HTL-WP characterization, component identification, and conversion path to reveal the changing mechanism of HTL-WP components. The mechanism of controllable intensity and selectivity was analyzed from two aspects: feedstock components and target strains. This study preliminarily establishes an approach for achieving targeted regulation of HTL-WP antibacterial intensity, which has significant reference value for the environmental-friendly reuse and functional targeted regulation of wastewater (liquid byproduct) from biowaste conversion in a specialized engineering-oriented perspective. It also provides novel utilization prospects for the valorization treatment of solid biowaste and promote the development and application of HTL technology.