Enrichment of Parachlorella kessleri biomass with bioproducts: oil and protein by utilization of beet molasses

Abstract

The aim of this study was to determine the suitability of beet molasses, an agro-industrial by-product, as an alternative culture medium component for photoheterotrophic and mixotrophic cultivation of Parachlorella kessleri. Application of beet molasses improved microalgal cell growth and modified the biochemical composition of P. kessleri biomass. During the addition of molasses to culture media with simultaneous aeration, the maximum biomass productivity, oil and protein productivity, and calorific value were 0.42 g L−1 day−1, 112.56 and 244.95 mg L−1 day−1, and 22.1 MJ kg−1, respectively. Under these conditions, the total content of polyunsaturated C16-C18 fatty acids decreased, which was suitable for application in biodiesel. Besides oils and carbohydrates, P. kessleri had an ability to synthesize significant amounts of proteins, especially during molasses utilization. This provides a possibility of a wide range of non-fuel applications of P. kessleri biomass.

Evaluation of the effects of sugarcane molasses as a carbon source for Ankistrodesmus gracilis and Haematococcus pluvialis (Chlorophyceae)

“…Lipid accumulation starts after nutrients used up for biomass growth. However, sugar cane molasses are a rich source of nitrogen, a very important constituent of protein synthesis and participates in cell division and growth (Piasecka et al, 2017). In current study, when high protein levels were compared to lipid levels, they were affected by high TIN concentrations ranging between 2.4 gL -1 (WC -H. pluvialis) and 5.1 gL -1 (NPK -A. gracilis) for two microalgae in mixotrophic cultivation.…”

“…However, if chlorophyll-a content of A. gracilis in autotrophic cultivation (Sipaúba-Tavares et al, 2017) is compared with mixotrophic cultivation, the concentration is 10-fold higher in culture with sugarcane molasses as a carbon source. In mixotrophic cultivation light and organic carbon source fulfil the same role in the growth and cellular composition of microalgae (Piasecka et al, 2017).…”

“…However, a cheap industrial by-product, such as sugarcane molasses, could be used as a low-cost medium supplement. Molasses consist of 50% total sugars, predominantly sucrose, since they contain significant amounts of reducing sugars such as glucose, fructose and other carbohydrates (Piasecka et al, 2017).…”

“…However, mixotrophic cultivation is the best approach to produce enhanced biomass and higher total lipid content because it uses phototrophic and heterotrophic modes of cultivation (Mondal et al, 2017). Up to the present, sugarcane molasses have been reported as a carbon source for the production of Botryococcus braunii, Chlorella vulgaris, C. sorokiana, C. zofingiensis, Haemotococcus pluvialis, Scenedesmus obliquus and Spirulina platensis biomass for astaxanthin or biodiesel production (Piasecka et al, 2017).…”

Agro-industrial by-product in photoheterotrophic and mixotrophic culture of Tetradesmus obliquus: Production of ω3 and ω6 essential fatty acids with biotechnological importance

“…The Kjeldahl method was used to determine the total nitrogen and protein content in the algal cells 10 . To calculate the total protein content, the total nitrogen content was multiplied by an algae-specific nitrogen-to-protein conversion factor of 5.95 55 in accordance with Eq.…”