Bioremediation of Crude Glycerol by a Sustainable Organic–Microbe Hybrid System

Abstract

Klebsiella pneumoniae with crude glycerol-utilizing and hydrogen (H2)-producing abilities was successfully isolated from return activated sludge from Shatin Sewage Treatment Works. The H2 production strategy used in this study was optimized with crude glycerol concentrations, and 1,020 μmol of H2 was generated in 3 h. An inorganic–microbe hybrid system was constructed with metal-free hydrothermal carbonation carbon (HTCC) microspheres to enhance the H2 production under visible light (VL) irradiation. Under optimized VL intensity and HTCC concentration, an elevation of 35.3% in H2 production can be obtained. Electron scavenger study revealed that the photogenerated electrons (e–) from HTCC contributed to the additional H2 production. The variation in intercellular intermediates, enzymatic activity, and reducing equivalents also suggested that the photogenerated e– interacted with K. pneumoniae cells to direct the metabolic flux toward H2 production. This study demonstrated the feasibility of using an inorganic–microbe hybrid system as a waste-to-energy technology.

Photobiocatalytic Solar Fuel and Solar Chemical Conversion: Sufficient Activity and Better Selectivity

“…Especially, screened K. pneumoniae were employed by our research group for PBS fabrication because they could utilize crude glycerol as precursors for H 2 production . This is the first time to introduce hydrothermally carbonized carbon (HTCC) into PBS.…”

“…For instance, wastewater was utilized for solar-driven hydrogen production, realizing both hydrogen production and wastewater treatment at low cost. 36 In another case, a hybrid system comprising HTCC and K. pneumoniae was established for solar driven H 2 production from crude glycerol, 19 which is a kind of industrial byproduct. Purification of crude glycerol is expensive and energy-intensive, so the hybrid system is capable of both bioremediation and efficient clean energy production.…”

“…The criteria for choosing photosensitizer nanomaterials have been summarized by Cestellos-Blanco et al, including tuning the bandgap (<3 eV) of nanomaterials to absorb visible light, matching the nanomaterial conduction potentials to potentials needed for biocatalysis, and selecting dimensions and surface charges of nanomaterials, as well as nanomaterial location and biocompatibility. Particularly, the biocompatibility of photo­sensitizers is very important and can be measured using colony-forming unit assays, respiratory activity (2,3,5-triphenyl­tetrazolium chloride dehydrogenase activity), and cell membrane integrity (intracellular K + leakage) . The multiomic approaches were also used to explore the impact of nanomaterials to cells .…”

“…Particularly, the biocompatibility of photosensitizers is very important and can be measured using colony-forming unit assays, 18 respiratory activity (2,3,5triphenyltetrazolium chloride dehydrogenase activity), and cell membrane integrity (intracellular K + leakage). 19 The multiomic approaches were also used to explore the impact of nanomaterials to cells. 20 For example, CdS induced the upregulation of genes associated with oxidative stress, heavy metal resistance, and DNA repair in Moorella thermoacetica cells.…”

Emerging Strategies for the Bioremediation of the Phenylurea Herbicide Diuron

“…Survival, proliferation, immobilization, competition with indigenous bacteria, and catalytic capacity are important factors influencing the biodegradation ability of inoculants ( Chen et al, 2013 ; Zhang et al, 2018 , 2021 ; Bhatt et al, 2019 ). In addition to environmental factors, the characteristics of the microbes themselves also have an important effect on their degradation ability ( Chan et al, 2021 ). Embedding functional enzymes and microbes with biomaterials or nanomaterials has been of increasing interest to facilitate in situ bioremediation.…”