Simultaneous production assessment of triacylglycerols for biodiesel and exopolysaccharides as valuable co-products in Navicula cincta

Hybrid two-stage culture of Halamphora coffeaeformis for biodiesel production: Growth phases, nutritional stages and biorefinery approach

“…Exopolysaccharides (EPS) are a further possible bioproduct. They mainly consist of glycoproteins and heteropolysaccharides [21,41] and can be classified as soluble EPS (S-EPS) or freely soluble in the aquatic environment, or bound EPS (B-EPS), associated with cell aggregates [21] (see Fig. 5a).…”

“…Soluble EPS production in culture represents a source of valuable bioproducts because these substances present interesting bio-active properties for the pharmaceutical industry and in agronomy [49e51]. The concentration of soluble EPS (S-EPS) in the supernatant of the H. coffeaeformis raceway pond was 27.97 mg L À1 , exceeding the value of N. cincta (18 mg L À1 ) [21], and those reported for several diatom species [49,52e55]. The highest concentrations of EPS cited in the literature in some diatom species were observed during the stationary growth phase in association with culture aging and nutrient deficiency [21,53,54,56].…”

“…Major economic bottlenecks that affect microalgal biofuel production include: culture, harvest, oil extraction and refining processes [14]. Benthic species, such as the one used in this study, form a biofilm that avoids the need to centrifuge large volumes of water, thus reducing harvest costs [11,21] which typically represent up to 20 or 30% of operating costs [22]. On the other hand, culture media used on a laboratory scale are too costly for industrial use.…”

“…However, their economic competitiveness will depend on eventual production costs. An additional distinctive feature of some species of diatoms is their capacity to produce exopolysaccharides (EPS) [21], which have potential applications in the pharmaceutical industry and in agronomy for the controlled delivery of products [30], or for bioremediation due to their adsorbent capacity [31].…”

Assessment of Halamphora coffeaeformis Growth and Biochemical Composition for Aquaculture Purposes

“…The specific growth rate (µ) was estimated by a least square fit to a straight line of the logarithmically transformed data, according to [8]. Biomass dry weight (DW) was determined as in [9,10], in triplicate, using pre-conditioned and pre-weighed filters (Whatman GF/C, Maidstone, UK). The filters containing 20 mL of each sample were washed three times and then dried at 100 • C until constant weight.…”