Page 46 - Aquauclature Research and Studies (01)

AQUAUCLATURE
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Research and Studies 1 (1): 15-01, 2026 page of 193

2015). Algal lipids can be extracted for biofuel production, while the remain-
ing solids, which consist mostly of proteins and carbohydrates, are suitable
for larval feed (Mondal et al., 2017).
In this study, the biomass yield, lipid, protein and carbohydrate produc-
tion from the marine algae Nannochloropsis oceanica will be investigated by
supplementing a standard F/2 inorganic medium at 75% concentration with
different organic carbon sources (fructose, lactose and glucose) and nitrogen
sources (poultry manure and rumen lysate), then evaluating the best condi-
tions to maximize whole cell biodiesel production and furthermore evaluating
the inclusion of the remaining defatted biomass to improve red tilapia culture.
MATERIALS AND METHODS
Algal species
The marine microalga Nannochloropsis oceanica obtained from algal
unit in the marine hatchery of the National Institute of Oceanography and
Fisheries, Alexandria, Egypt. The algal strain was cultured in sea water en-
riched with F/2 medium (Guillard and Rhyter,1962) and the salinity of sea-
water was (35±1 ppt).
The Experimental design
This experiment was conducted in two phases: The first phase was to
evaluate the effect of different carbon sources [fructose (A), lactose (B), glu-
cose (C)] and nitrogen sources [poultry manure extract (PM) and rumen ly-
sate (RL)] at a ratio of 75:25% to F/2 medium for the cultivation of microal-
gae N. oceanica compared to the control group (100% F/2). The cultivation
system was started indoors at a rate of (250 ml - 5 L) and was then scaled up
in outdoor mass cultures at a rate of (45 L of plastic bags) in triplicate to
determine the growth in terms of biomass and biochemical composition as
well as biodiesel production at the end of the exponential growth phase of
these cultures. The different sources were prepared in the medium at concen-
trations of 0.5 g/L, and the remaining F/2 medium was added at a concentra-
tion of 50% as shown in Table 1. The cultivation period was 10 days, and the
algal biomass was harvested and quantified.