Innovative polyhydroxybutyrate production by Chlorella fusca grown with pentoses.

The current study aimed to evaluate if the addition of pentoses along with variations in light intensity and photoperiod can stimulate the production of polyhydroxybutyrate (PHB) and other biomolecules by Chlorella fusca LEB 111. The variables evaluated were the addition of xylose and arabinose as sources of organic carbon, different photoperiods (18 h, 12 h and 6 h light) and variations in light intensities (58, 28 and 9 µmolphotons m-2 s-1). The highest PHB accumulation (17.4% w w-1) and protein production (53.2% ww-1) were observed in assays with xylose addition and a photoperiod of 6 h of light provided at 28 and 58 µmolphotons m-2 s-1, respectively. The highest lipid content (24.7% w w-1) was obtained with 18 h of light. The current study contributes to the development of sustainable alternatives for the use of wastes and the production of biomolecules from algae.

Pentoses and light intensity increase the growth and carbohydrate production and alter the protein profile of Chlorella minutissima.

High concentrations of carbon, which is considered a necessary element, are required for microalgal growth. Therefore, the identification of alternative carbon sources available in large quantities is increasingly important. This study evaluated the effects of light variation and pentose addition on the carbohydrate content and protein profile of Chlorella minutissima grown in a raceway photobioreactor. The kinetic parameters, carbohydrate content, and protein profile of Chlorella minutissima and its theoretical potential for ethanol production were estimated. The highest cellular concentrations were obtained with a light intensity of 33.75µmol.m-2.s-1. Arabinose addition combined with a light intensity of 33.75µmol.m-2.s-1 increased the carbohydrate content by 53.8% and theoretically produced 39.1mL·100g-1 ethanol. All of the assays showed that a lower light availability altered the protein profile. The luminous intensity affects xylose and arabinose assimilation and augments the carbohydrate content in C. minutissima, making this microalga appropriate for bioethanol production.