Chlorella vulgaris mixotrophic growth enhanced biomass productivity and reduced toxicity from agro-industrial by-products

Abstract

Algal wastewater remediation has become attractive for a couple of years now, however the effectiveness of genetic toxicity reducing of some by-products through microalgae are still not well reported. This study aimed to evaluate the growth, nutrients and toxicity removal of Chlorella vulgaris cultivated under autotrophic and mixotrophic conditions in three agro-industrial by-products. Mixotrophic culture using corn steep liquor showed higher cell concentration, specific growth rate, maximum cell productivity and biomass protein content when compared to cheese whey and vinasse. Nutrient removal results showed that C. vulgaris was able to completely remove corn steep liquor nutrients, while in cheese whey and vinasse culture this removal was not as efficient, observing remaining COD. This work evaluated for the first time the corn steep liquor and cheese whey genetic toxicity through Allium cepa seeds assay. These results demonstrate that corn steep liquor toxicity was totally eliminated by C. vulgaris cultivation, and cheese whey and vinasse toxicity were minimized. This study proves that the mixotrophic cultivation of C. vulgaris can increase cellular productivity, as well as it is a suitable and economic alternative to remove the toxicity from agroindustrial by-products.

Microalgae wastewater treatment: Biological and technological approaches

“…Along with photoautotrophy, several microalgal species are capable of performing chemoheterotrophic or mixotrophic metabolism, which is of interest for the treatment of industrial wastewater containing a high organic load. Among the most studied conventional microalgal strains is Chlorella vulgaris, which has been examined recently for its biomass production from food waste compost [23], sludge extracts [24], corn steep liquor, cheese whey and vinasse [25], textile waste effluent [26], tofu wastewater [27], and industrial dairy effluent [28]. Zhai et al [19] have demonstrated the high N (81.51%) and P (80.52%) removal efficiency of the widely used cyanobacterium Arthrospira platensis using a synthetic wastewater.…”

Microalgae Growth under Mixotrophic Condition Using Agro-Industrial Waste: A Review

“…Melo et al [74] evaluated the growth, nutrients and toxicity removal of Chlorella vulgaris cultivated under autotrophic and mixotrophic conditions using corn steep liquor, cheese whey and vinasse as source of organic matter. The results demonstrated that corn steep liquor toxicity was totally eliminated and cheese whey and vinasse toxicity were minimized by C. vulgaris.…”

Bio-remediation of Most Contaminated Sites by Heavy Metals and Hydrocarbons In Dhiba Port Kingdom of Saudi Arabia Using Chlorella Vulgaris

“…In this case, it is preferred for alga to grow under mixotrophic conditions and use hydrocarbon as the sole carbon source. Melo et al (2018) proved that when C. vulgaris was grown under mixotrophic conditions, the cellular productivity increased, and it becomes more effective to remove agro industrial by-products. The highest growth rate of C. vulgaris was obtained when grown under mixotrophic conditions than when grown under photoautotrophic conditions (Abreu et al, 2012).…”