Microalgae-Based Wastewater Treatment and Biofuel Production: Strain Selection, Pollutant Utilization, and Integrated Biorefinery Strategies
摘要
Concerns over rising oil prices, dwindling reserves, and increasing greenhouse-gas emissions have intensified the search for sustainable alternatives to fossil fuels. Microalgae are an emerging third-generation feedstock due to their rapid growth, high photosynthetic efficiency, and flexible trophic modes, which allow production on non-arable land and in wastewater. Microalgae have high potential for growth and lipid accumulation, as well as carbohydrate and protein content intracellularly, which can be converted to biofuels, which are deeply discussed. Strategies for the cultivation of microalgae in wastewater while providing simultaneous pollutant removal are elaborated. Screening, identification, and cultivation conditions for potential microalgae used in renewable energy production are also reviewed. Several strategies (such as low-cost media and abiotic stresses) applied to develop raw materials for energy are also highlighted. Microalgal biomass yielded biomethane and biohydrogen production by 241–396.21 NmLCH4/g VS and 22.0–92.9 mL H2/g, respectively. Micractinium conductrix, Choricystis parasitica, and Monoraphidium sp. are reported for biodiesel while Botryococcus braunii, Hindakia tetrachotoma, and Spirulina subsalsa were reported for hydrocarbon, bioethanol, and biogas-based biofuels, respectively. Integrating wastewater-based cultivation with multi-product biorefinery processes represents the most promising pathway to economically viable and sustainable microalgal biofuels generation in the near future.
Graphical Abstract