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Volume 9
Journal of Bioremediation & Biodegradation
ISSN: 2155-6199
Biofuel Congress 2018 &
Biomass 2018
September 04-06, 2018
JOINT EVENT
September 04-06, 2018 | Zurich, Switzerland
13
th
Global Summit and Expo on
Biomass and Bioenergy
&
12
th
World Congress on
Biofuels and Bioenergy
Microalgae cultivation in continuous reactor using mixotrophic anaerobic effluent: effect of dilution
rate on biomass productivity and tertiary treatment
Servio Tulio Cassini, Marcos V N L Pereira, Aline Dassoler
and
Ricardo F Goncalves
UFES, Brazil
M
icroalgae are continuously attracting main attention from biomass researchers, especially due to their capacity of
fast growth, CO
2
abatement and land-free cultivation as compared with conventional crops. Additionally, municipal
wastewater has been long recognized as a suitable media for the cultivation of microalgae biomass. Culturing microalgae
with wastewater effluents also promotes a process of tertiary treatment, characterized by removal of main nutrients (N, P)
from wastewater and simultaneously achieving high biomass productivities. However, few studies report data concerning
biomass productivity in continuous mode using unsterilized mixotrophic wastewater effluent and we found no reports of E.
coli population decay rates in these continuous reactors. This study focuses on the selection of native microalgae strains that
are applicable for biomass production and tertiary wastewater treatment in continuous mode. Five strains were isolated and
cultivated in unsterilized anaerobic effluent in batch growth mode, to identify the efficient microalgae isolates for biomass
conversion. The isolate L06 (Chlorella sp.) was selected and evaluated based on five dilution rates from 0.1 to 0.5 1/day on
continuous growth reactor, resulting in five steady state conditions. Maximal volumetric biomass productivity of 294 mg/L day
was obtained at 0.3 1/day without CO
2
addition or air bubbling. Carbohydrates were the major fraction of the dried biomass,
followed by proteins and then lipids. The highest removal rates of total nitrogen and phosphorus from the liquid phase were
13.0 and 1.4 mg/L day, respectively, and were achieved at 0.4 1/day. The maximal decay rate for E. coli (3.7 1/day) was also
achieved at this dilution rate, representing approximately a 99.9% population reduction of this bioindicator over a period of 2.5
days. Therefore, L06 – Chlorella sp. continuous cultivation using secondary-treated wastewater can be adjusted depending on
its objective: for biomass production, a dilution rate of approximately 0.3 1/day is recommended; and for tertiary treatment a
rate of 0.4 l/day is suggested.
Recent Publications
1. Caporgno et al. (2015) Microalgae cultivation in urban wastewater: Nutrient removal and biomass production for biodiesel
and methane. Algal Research 10:232-239
2. Gonçalves A L, Pires J C M and Simões M (2016) Biotechnological potential of Synechocystis salina co-cultures with
selected microalgae and cyanobacteria: Nutrients removal, biomass and lipid production. Bioresource Technology 200:279-
286.
Servio Tulio Cassini et al., J Bioremediat Biodegrad 2018, Volume 9
DOI: 10.4172/2155-6199-C1-014