From waste to resource: Effects of digested rotten potato supernatant on the growth, total biomass and nutrient composition of Chlorella vulgaris

Abstract

A study was carried out to evaluate the growth performance of Chlorella vulgaris, a green microalga, in three different concentrations of digested rotten potato supernatant (DRPS) for 16 days. C. vulgaris was grown in 20 % (T1), 40 % (T2), and 60 % (T3) of the DRPS and at the same time in Bold Basal Medium (BBM) as a control (T4). A significantly highest cell density of C. vulgaris was found in T1 (192.83 ± 1.75 × 105 cells mL−1) in comparison to T2 (136.83 ± 5.58 × 105 cells mL−1), and T3 (99.11 ± 5.38 × 105 cells mL−1) (p < 0.001 for all comparisons) while the cell density at T1 (192.83 ± 1.75 × 105 cells mL−1) and T4 (180.907 ± 4.58 × 105 cells mL−1) did not differ significantly (p = 0.227). Moreover, the mean daily division rate of C. vulgaris was significantly higher in T1 (0.340 ± 0.001 divisions day−1) in comparison to other concentrations of DRPS (p < 0.001 for all comparisons). The maximum value of total biomass (1.07 ± 0.10 g L−1) was found in T1 which was statistically similar to those in T4 and T2. In addition, there was no significant difference between the mean maximum values of chlorophyll-a content and optical density of C. vulgaris in T1 and T4. The highest protein content of 42.67 ± 0.57 % was observed in T4 which was significantly higher than T1 (39.43 ± 1.67 %) (p = 0.027). It is also worth mentioning that there was no significant difference in the crude lipid content of the microalgae grown in T1 (10.06 ± 0.17 %) and T4 (9.88 ± 0.14 %) (p = 0.616). Hence, 20 % DRPS can be used as an alternative culture media of BBM for C. vulgaris with a broad aim to accelerate the sustainable advancement of microalgal production.

Keywords

• Vegetable waste
• Low-cost media
• Microalgal culture
• Biomass production
• Lipid-protein composition