Concerns about environmental safety have led to strict regulations on the discharge of final brewery effluents into water bodies. Brewery wastewater contains huge amounts of organic compounds that can cause environmental pollution. The microalgae wastewater treatment method is an emerging environmentally friendly biotechnological process. Microalgae grow well in nutrient-rich wastewater by absorbing organic nutrients and converting them into useful biomass. The harvested biomass can be used as animal feed, biofertilizer, and an alternative energy source for biodiesel production. This review discusses conventional and current brewery wastewater treatment methods, and the application and potential of microalgae in brewery wastewater treatment. The study also discusses the benefits as well as challenges associated with microalgae brewery and other industrial wastewater treatments.

Haematococcus pluvialis, as the best natural resource of astaxanthin, is widely used in nutraceuticals, aquaculture, and cosmetic industries. The purpose of this work was to compare the differences in astaxanthin accumulation between motile and nonmotile cells of H. pluvialis and to determine the relationship between the two cells and astaxanthin production. The experiment design was achieved by two different types of H. pluvialis cell and three different light intensities for an eight day induction period. The astaxanthin concentrations in nonmotile cell cultures were significantly increased compared to motile cell cultures. The increase of astaxanthin was closely associated with the enlargement of cell size, and the nonmotile cells were more conducive to the formation of large astaxanthin-rich cysts than motile cells. The cyst enlargement and astaxanthin accumulation of H. pluvialis were both affected by light intensity, and a general trend was that the higher the light intensity, the larger the cysts formed, and the larger the quantity of astaxanthin accumulated. In addition, the relatively low cell mortality rate in the nonmotile cell cultures indicated that the nonmotile cells have a stronger tolerance to photooxidative stress. We suggest that applying nonmotile cells as the major cell type of H. pluvialis to the induction period may help to enhance the content of astaxanthin and the stability of astaxanthin production.

Pseudodiaptomus dubiais a calanoid copepod that is distributed widely in the estuarine-coastal waters of Asia and is a dominant copepod in the shrimp grow-out ponds in southern China. A laboratory culture experiment was conducted to evaluate the influences of water temperature on larval development, survival, and reproduction. Results indicate that within a temperature range from 15 to 35°C, larval development increases as the temperature increases. The water temperature for optimal larval survival rate ranges from 20 to 35°C. Longevity and egg hatching time decrease as the temperature increases from 20 to 35°C. Total fecundity and reproduction frequency increase as the water temperature increases, with the maximum at 30°C. Fecundity and reproduction frequency decrease when the temperature exceeds 30°C. Intrinsic growth rate (r_m) ranges from 0.168 to 0.195 at 25 to 30°C; net reproduction rate (R₀) and finite growth rate (?) are 163 to 264 and 1.183 to 1.215, respectively, when the temperature is greater than 20 and 35°C; population doubling time (t) varies from 3.556 to 4.128 days at temperatures less than 20 and 35°C. Population generation time (T) is negatively correlated with temperature, with the optimal population growth rate at 25 to 30°C.

The current commercial production of natural astaxanthin is mainly carried out using Haematococcus pluvialis vegetative cells in the “two-stage” batch mode. The motile vegetative cells are more sensitive to stress than nonmotile vegetative cells, thereby affecting the overall astaxanthin productivity in H. pluvialis cultures. In this study, we compared the differences between motile cells and nonmotile cells in astaxanthin productivity, morphological changes, the mortality rate, and the diameter of the formed cysts. The experimental design was achieved by two different types H. pluvialis cell under continuous light of 80 μmol photons m⁻² s⁻¹ for a 9-day induction period. The highest astaxanthin concentration of 48.42 ± 3.13 mg L⁻¹ was obtained in the nonmotile cell cultures with the highest the productivity of 5.04 ± 0.15 mg L⁻¹ day⁻¹, which was significantly higher than that in the motile cell cultures. The microscopic examination of cell morphological showed a large number of photooxidative damaged cells occurring in the motile cell cultures, resulting in higher cell mortality rate (22.2 ± 3.97%) than nonmotile cell cultures (9.6 ± 0.63%). In addition, the analysis results of cell diameter statistics indicated that nonmotile cells were more conducive to the formation of large astaxanthin-rich cysts than motile cells. In conclusion, the works presented here suggest that the accumulation of astaxanthin was significantly improved by nonmotile cells of H. pluvialis, which provided a possibility of optimizing the existing H. pluvialis cultivation strategy for the industrial production.