An Overview of Green Bioprocessing of Algae-Derived Biochar and Biopolymers: Synthesis, Preparation, and Potential Applications

Abstract

Algae have the potential to be used as a feedstock for the synthesis of valuable compounds and biofuels. In addition, algal waste can be further transformed into biofuel, biogas, and biochar using different thermochemical processes such as microwave pyrolysis, pyrolysis, torrefaction, and hydrothermal conversion. Due to its high specific surface area, rapid electron transport, and graphitic carbon structure, algal biochar carbonized at high temperatures has shown outstanding performance for applications as CO2 adsorbents, supercapacitors, and persulfate activation. Due to the combination of various functional groups and porous structures, the algae biomass pyrolysis at a moderate temperature produced high-quality biochar that shows high performance in terms of pollutant removal, while low-temperature pyrolysis produces coal fuel from algae via torrefaction. Over time, there have been exponentially more petroleum-based polymers created that have harmful impacts on both humans and the environment. As a result, researchers are becoming more interested in algae-based biopolymers as a potential alternative strategy for establishing a sustainable circular economy globally. The advantages of microalgal biopolymer over other feedstocks are its capacity to compost, which provides greenhouse gas credits, its quick growth ability with flexibility in a variety of settings, and its ability to minimize greenhouse gas emissions.

Macroalgae Bioplastics: A Sustainable Shift to Mitigate the Ecological Impact of Petroleum-Based Plastics

“…Fucoidan, a polysaccharide found in brown algae, contains different percentages of l-fucose and sulfate ester groups based on the species (Figure 2) [90]. It can be used as a feedstock for the production of alginate, a biopolymer that has applications in the food and pharmaceutical industries [91].…”

Biochar/Biopolymer Composites for In-Situ Groundwater Remediation

“…Despite the improved properties, synthetic and petroleum-based polymers suffer from a lack of biodegradability. Thus, biopolymers such as polylactic acid (PLA), poly(3-hydroxybutyrate) (PHB), starch-based polymers, and biopolymers from algae biomass have the potential to be used as valuable flexible matrices to produce high-quality biochar composites and to establish a sustainable circular economy globally [40,41]. Nevertheless, biopolymer-based BC composites still require optimization to reach performances comparable to traditional active carbon materials and take advantage over the synergistic effects of biochar dispersed in polymers.…”