Microalgal bioremediation of CO 2 , nutrients, endocrine disruptors, hydrocarbons, pesticides, and cyanide compounds have evaluated comprehensively. Microalgal mitigation of nutrients originated from municipal wastewaters, surface waters, and livestock wastewaters has shown great applicability. Algal utilization on secondary and tertiary treatment processes might provide unique and elegant solution on the removing of substances originated from various sources. Microalgae have displayed 3 growth regimes (autotrophic, heterotrophic, and mixotrophic) through which different organic and inorganic substances are being utilized for growth and production of different metabolites. There are still some technology challenges requiring innovative solutions. Strain selection investigation should be directed towards identification of algal that are extremophiles. Understanding and manipulation of metabolic pathways of algae will possible unfold solution to utilization of algae for mitigation of dissolve organic nitrogen in wastewaters.

Polysaccharide derivatives have attracted attention as sustainable and renewable sources of bioactive compounds. This review presents recent studies on the derivatization techniques and the biological properties of polysaccharide derivatives, including sulfated-, acetylated-, phosphorylated-, carboxymethylated-, aminated-, benzyolated-, C-glycosylated-, hydroxypropylated- and selenized-polysaccharides. The introduction of a new functional group(s) to native polysaccharides altered their physical, chemical, and most especially biological properties. Biological properties of polysaccharide derivatives depend on the molecular weight, type of modification, type of native polysaccharide, modification process conditions, solubility, and conformation. However, certain derivatives of some polysaccharides and hybrid derivatives (with multiple functional groups) have received less attention. Intentionally, derivatives of well-known polysaccharides (cellulose, starch, heparin, chitin, and chitosan) have been excluded from this review.

Plants and algae contain novel biocompounds with therapeutic potentials. These compounds are either embedded within the cell wall matrix or bonded with polymers at cell cytoplasm, which hinders release of bioactive compounds during extraction. Enzymatic hydrolysis of cell wall and cytoplasm polymers enhances the release of biocompounds while preserving their biological potencies. Previous works have focused more on comparative studies of different enzymes, whereas other process parameters, such as agitation speed, substrate particle sizes, hydrolysis time, degree of hydrolysis, and multistage extraction, have received less attention. This review examines the extent of studies in this area and highlight current research gaps to be explored in future researches.

Food production heavily depends on ammonia-containing fertilizers to improve crop yield and profitability. However, ammonia production is challenged by huge energy demands and the release of ~2% of global CO₂. To mitigate this challenge, many research efforts have been made to develop bioprocessing technologies to make biological ammonia. This review presents three different biological approaches that drive the biochemical mechanisms to convert nitrogen gas, bioresources, or waste to bio-ammonia. The use of advanced technologies—enzyme immobilization and microbial bioengineering—enhanced bio-ammonia production. This review also highlighted some challenges and research gaps that require researchers’ attention for bio-ammonia to be industrially pragmatic.

The chemical structure of three sulfated polysaccharides fractions (TtF1, TtF2, and TtF3) obtained from anion-exchange separation of aqueous extracts of brown seaweed (Turbinaria turbinate) were studied. The infrared spectra patterns showed that the fractions possess functional groups similar to that of sulfated polysaccharides. The sulfated polysaccharides fractions exhibited molecular weights of 223.5, 495.5, and 326.05 kDa, respectively, for TtF1, TtF2, and TtF3. ¹H NMR spectra of TtF2 and TtF3 contain α-anomeric protons (5–5.6 ppm), ring protons (3.4–4.4), and methyl protons (1–1.3 ppm) while that of TtF1 only exhibited ring protons and methyl protons. Rheological data were fitted to power law which revealed that the fractions were Newtonian and/or presented weak pseudoplastic behavior. Consistency values increased with concentration in all fractions. Consistency values of TtF2 were the highest, followed by TtF1 and then TtF3. Thermal degradation patterns of TtF1 and TtF2 were similar but different from that of TtF3. This study confirmed that chemical and physical characteristics of sulfated polysaccharides fractions are interrelated and provided in-depth understanding of sulfated polysaccharides of brown algae.