INTRACELLULAR, CELL-BOUND, AND EXTRACELLULAR POLYSACCHARIDES PRODUCTION FROM PORPHYRIDIUM CRUENTUM: EFFECT OF ORGANIC CARBON TO NITROGEN RATIO AND PHOTOPERIOD

• Main Author: Maria, Regina
• Format: Theses
• Language: Indonesia
• Subjects: Teknik kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/75954
• Institution: Institut Teknologi Bandung

<p align="justify">Polysaccharides are important macromolecules in the food, cosmetic, nutraceutical, and therapeutic industries due to their rheological properties and health benefits. These polysaccharides can be categorized into three groups based on their location in microalgae: intracellular polysaccharides (IPS), lipopolysaccharides/cell-bound polysaccharides (CBPS), and extracellular polysaccharides (EPS). Particularly, extracellular polysaccharides produced by microalgae have advantages because of their ease of extraction and the presence of functional groups such as sulfate and methyl. One potential microalga that produces EPS with antioxidant properties is Porphyridium cruentum. Despite the increasing global demand for polysaccharides, the production of polysaccharides from microalgae has not been extensively studied and remains costly. One way to reduce the high production cost of polysaccharides from microalgae is by using mixotrophic cultivation methods that utilize organic carbon sources to promote cell growth and product formation. Additionally, environmental variations, such as the photoperiod (light period), also play a crucial role in microalgae growth. This research aims to examine several factors influencing biomass growth and polysaccharide production, particularly EPS and IPS and CBPS (ICBPS) in P. cruentum. The factors to be tested include the carbon-to-nitrogen ratio and photoperiod using tofu waste as a medium to lower EPS production costs. Glycerol will be added to the culture at concentrations of 5, 10, 15, and 20 g/L to achieve carbon-to-nitrogen ratios (C/N) of 120.95, 160.78, 217.9, and 395.1, respectively. Glycerol is chosen because it is a byproduct of the transesterification process in the biodiesel industry, making it economically affordable and environmentally friendly. The photoperiod will be varied between 18:6 and 12:12 hours (light:dark) to test their effects on biomass growth and EPS production. The highest biomass and total polysaccharide yield were achieved at a C/N ratio of 395.1 with an 18:6 photoperiod during a 7-day cultivation period, resulting in 13.64 g/L biomass (specific growth rate of 1.2/day) and 1.46 g/L total polysaccharides. Increasing the C/N ratio in mixotrophic culture led to higher concentrations of biomass and total polysaccharides in P. cruentum, increasing from 7.03 to 13.65 g/L and from 0.98 to 1.46 g/L, respectively. Moreover, utilizing P. cruentum in tofu waste also showed significant advantages, with a 63.43% reduction in Chemical Oxygen Demand (COD). The regulation of the carbon-to-nitrogen ratio, use of low-cost carbon sources, and increasing the photoperiod can significantly promote sulfate polysaccharide production in P. cruentum, indicating its potential application in various industries, such as nutraceuticals, therapeutics, cosmetics, and food.