The Effect of Tofu Wastewater and pH on the Growth Kinetics and Biomass Composition of Euglena sp.

Abstract

Media and pH are two crucial factors in microalgal cultivation. Industrial wastewater such as tofu wastewater can be utilized as alternative media for growing microalgae like Euglena sp. to produce biomass as feedstock in biorefinery activities. Here, we evaluated combinations of tofu wastewater (L) consisting of 0% (L1), 75% (L2), and 100% (L3) with pH (P) levels consisting of 5.0 (P1), 5.5 (P2), 6.0 (P3), 6.5 (P4), and 7.0 (P5). The analyses were carried out on the growth kinetics, biomass, primary metabolite compounds, and pigments of Euglena sp. Based on the study, the combinations with the highest cell density, biomass, maximum carbohydrate content, maximum lipid content, and protein content were L2P2 (23.13x105 cells/ml), L2P1 (4.53±0.17 mg/ml), L1P5 (0.93±0.02 mg/ml), L2P1 (1.27±0.11 mg/ml), and L3P4 (256±26.86 ppm), respectively. Moreover, the combinations with the highest chlorophyll-a, chlorophyll-b, and carotenoid were L2P4 (33.53±0.13 mg/l), L2P2 (17.73±0.50 mg/l), and L2P2 (11.65±0.00 mg/l), respectively. The addition of tofu wastewater combined with specific pH level enhanced the growth and biomass composition of Euglena sp. (P<0.05), with the exception of carbohydrate content. Additionally, each biochemical component of Euglena sp. had a different optimum combination of tofu wastewater and pH level. However, this wastewater can potentially be used as an alternative medium for cultivating this microalga in order to cut the production costs of biorefinery activity.

The Utilization of Hydroxyapatite as Green Fertilizer Increasing Soil Fertility

“…Various kinds of waste have been reported to be used as nutrient sources for the growth of an organism including plants. Utilization of organic-rich nutrient components can reduce production costs and increase the yield of agricultural production [6,7]. Hydroxyapatite is a source of green fertilizer that can be produced from various types of waste, such as shellfish, shell egg, and fish bone (Figure 1).…”

Reddening of the Unicellular Green Alga Euglena gracilis by Dried Bonito Stock and Intense Red Light Irradiation

“…Beyond these typical synthetic growth mediums, studies have been conducted using food and its by-products as substrates for the growth and upcycling of E. gracilis . These studies employed plant-based foods (tomato juice [ 31 ], spent tomato byproduct (STB) [ 35 ], potato liquor [ 36 ], corn steep solid [ 37 ], corn steep liquor and brewer’s spent grain [ 38 ], kinnow peel extract [ 39 ], tofu wastewater [ 40 ], and a mixture of sewage and organic wastes (molasses, corn steep liquor, and waste wine) [ 41 ]). Our research is the first to use an animal-based food (Katsuo dashi; Bonito stock) in this context.…”

Method for growing edibleEuglena gracilisin an inexpensive medium with tomato juice to a high cell density equivalent to the density in KH medium

“…With producing E. gracilis using food-grade highly sterilized food processing by-products, the product is applicable to functional foods and pharmaceuticals. Specifically, potato liquor, 23 corn steep solid, 24 corn steep liquor and brewer's spent grain, 25 kinnow peel extract, 26 tofu wastewater, 27 mixture of sewage and organic wastes (molasses, corn steep liquor, and waste wine) 28 and Spent Tomato Byproduct (STB) 29 have been used to grow E. gracilis to efficiently and economically produce paramylon. In growth using STB, hydrolysis treatment of STB and adjustment to the appropriate pH enabled the production twice the amount of biomass of CM medium.…”