Enhancement of targeted microalgae species growth using aquaculture sludge extracts

Abstract

Natural growth-promoting nutrients extracted from aquaculture sludge waste can be used to maximise microalgal growth. This study identified the influence of aquaculture sludge extract (SE) on four microalgae species. Conway or Bold's Basal Media (BBM) was supplemented with SE collected from a Sabak Bernam shrimp pond (SB) and Kota Puteri fish pond (KP), and tested using a novel microplate-incubation technique. Five different autoclave extraction treatment parameters were assessed for both collected SE, i.e., 1-h at 105 °C, 2-h at 105 °C, 1-h at 121 °C, 2-h at 121 °C, and 24-h at room temperature (natural extraction). Microalgae culture in the microplates containing control (media) and enriched (media + SE) samples were incubated for nine days, at 25 °C with the light intensity of 33.75 μmol photons m −2 s −1 at 12-h light/dark cycle. The total dissolved nitrogen (TDN) and total dissolved phosphorus (TDP) in KP SE were 44.0–82.0 mg L −1 and 0.96–8.60 mg L −1 . TDN (8.0%–515.0%) and TDP (105%–186 %) were relatively higher in KP SE compared to SB SE. The growth of microalgae species Nannochloropsis ocenica showed significant differences ( p < 0.05) between the five extraction treatments from SB and the control. However, Chlorella vulgaris , Neochloris conjuncta , and Nephroclamys subsolitaria showed no significant differences ( p > 0.05) in SB SE. N. ocenica , C. vulgaris , and N. conjuncta showed significant differences ( p < 0.05) between five extraction treatments from KP and the control while N. subsolitaria showed no significant difference ( p > 0.05). The specific growth rate (SGR) in the exponential phase of all microalgae species were relatively higher in SB SE compared to KP SE. While the organic matter content of KP SE was relatively higher, there were no significant differences in microalgae growth compared to SB SE. Nonetheless, modified SE did influence microalgae growth compared to the control. This study shows that modified SE could be used as enrichment media for microalgae cultivation.

Kinetics Growth and Recovery of Valuable Nutrients from Selangor Peat Swamp and Pristine Forest Soils Using Different Extraction Methods as Potential Microalgae Growth Enhancers

“…[ 23 ] reported that C. vulgaris showed higher nitrogen requirements for growth. Study by [ 24 ] reported that modified soil extract from sludge pond did influence microalgae growth C. vulagaris and N. oceanica compared to the control. Although results were presented using optical density, correlation between optical density and number of cells is presented in Figure S1 (Supplementary S1) .…”

Experiment and Kinetic Modeling of Soil Extract Effects on Dunaliella Primolecta Growth

“…Figure 3 shows light intensity limitation, part of the terms in Equation (11). The SE and temperature are fixed at 2 mL and 25°C, respectively.…”

“…The microplate-incubation technique 11 was conducted for the microalgae at 5 different SE volumes and concentration; 1, 2, 3, 6, and 10 mL, with the percentage (%) of 0%, 0.5%, 1%, 1.5%, 3%, and 5%, respectively. Media without SE was used as the control media in another microplate.…”

“…The governing equation is established by substituting Equation ( 10) into Equation ( 2), as shown in Equation (11).…”

“…Anaerobically treated sediments from the dairy waste area were also used as a nutrient source for bioenergy production by algae 10 . Studies by 11 and 12 have shown that soil extract from aquaculture sludge and forest soil has great potential as the enrichment media for microalgae cultivation.…”