Contribution of glycerol addition and algal–bacterial cooperation to nutrients recovery: a study on the mechanisms of microalgae‐based wastewater remediation

Abstract

BACKGROUND: Microalgae biotechnology is considered as a promising way to recover nutrients from centrate wastewater for value-added biomass production, but it is rarely adopted in a real-world application. Current study confirmed that carbon deficiency and suspended solids are two problems jeopardizing the microalgae-based wastewater remediation. In this regard, glycerol was added into centrate wastewater as exogenous carbon source and algal-bacterial cooperation for nutrients recovery assessment. RESULTS:The results showed that glycerol addition increased the biomass yield of algae from 1.54 to 2.58 g L −1 in 5-day culture and, at the same time, improved the removal efficiency of nitrogen and phosphorus, which were further assessed by pilot-scale experiments. Bacterial community analysis indicated that algal-bacterial cooperation involves carbon dioxide and oxygen exchange, phosphorus absorption, and solid organics degradation, forming a complementary nexus beneficial for wastewater treatment.CONCLUSION: Glycerol is proven to be a good carbon source for microalgae growth in the centrate wastewater. Additionally, the cooperation between microalgae and bacteria plays a key role in the nutrients removal during centrate wastewater. It is expected the technology and knowledge provided by current work can further promote the industrialization of microalgaebased wastewater remediation. Figure 6. Scheme for microalgae-based centrate wastewater treatment and mechanism of nutrients recovery. www.soci.org M Xu et al.wileyonlinelibrary.com/jctb

Valorization of sawdust biomass for biopolymer extraction via green method: Comparison with conventional process

“…XRD patterns were collected in a Bruker diffractometer (D8 Advanced model), equipped with Bregg Bentano geometry, from 10 to 50 (2θ) range at 40.0 kV and 40.0 mA, using CuK α radiation (λ = 0.154 nm), 0.02 per step. The main signal of XRD patterns (19)(20)(21)(22)(23)(24)(25)(26)(27)(28) were analyzed through peak deconvolution of integrated profiles. Specifically, type I and II polymorphous contributions were studied to know their presence.…”

“…For example, steam explosion and fiber explosion, technologies of pretreatment using high‐pressured saturated steam, are able to reduce fiber size and improve accessibility of cellulose for its further degradation, but with the disadvantage of recovering a low polymerization degree 26 . Additionally, it has some limitations with respect to the incomplete disruption of lignin‐carbohydrate matrix and high content lignin 27 . Pretreatments can be either physical (eg, milling, grinding, microwave, sonication, and pyrolysis) or a physicochemical process (ammonia, supercritical fluids) 28 .…”

“…The removal of H and L, can also be done using green methods (GMs) including hydrogen peroxide (H 2 O 2 ) and sodium hydroxide reagents for bleaching process 41 . In comparison with chlorine methods, which release hazardous pollutants, 42 H 2 O 2 decomposes into non‐toxic products such as oxygen and water, 27 reason why it is classified as eco‐friendly 43 . On the other hand, the use of NaOH, is highly efficient to degrade lignin through free radicals 44 enhancing the delignification 45 .…”

“…26 Additionally, it has some limitations with respect to the incomplete disruption of lignincarbohydrate matrix and high content lignin. 27 Pretreatments can be either physical (eg, milling, grinding, microwave, sonication, and pyrolysis) or a physicochemical process (ammonia, supercritical fluids). 28 In addition, biological pretreatments involving bacteria, fungi and metabolites such as enzymes to hydrolyze and degrade L, H and C. This method has the advantage of being free of chemicals, however, it is a very slow process.…”

Emerging technologies of employing algae and microorganisms to promote the return-to-field of crop straws: A mini-review

“…In our view, some measures can be taken to lower the production cost of microalgae. Firstly, wastewater enriched with nutrients can be employed to cultivate microalgae ( Xu et al, 2020 ; Zhong et al, 2021 ). Compared to artificial culture media, wastewater can be obtained at much lower cost, reducing the production cost of microalgae.…”