Pembuatan Asam Sitrat Melalui Proses Fermentasi Padat Kulit Jeruk Citrus Reticulata dengan Variasi Waktu: Production of Citric Acid Through Solid Fermentation of Citrus Reticulata Peel with Variations in Time

Abstrak

Citric acid is an important organic acid that plays a wide role in various industries, especially food and beverages, which account for about 75% of global demand. In addition, this acid is also used in the pharmaceutical, cosmetic, biotechnology, and environmental processing fields. With increasing demand and awareness of sustainability, solid fermentation-based production methods using Aspergillus niger have become an environmentally friendly alternative to chemical synthesis. Orange peel waste has great potential as a fermentation substrate because it contains pectin, soluble sugars, hemicellulose, and cellulose, which serve as carbon sources. This study aims to examine the effect of fermentation duration on citric acid formation. The research stages included orange peel pretreatment, fermentation medium preparation, Aspergillus niger culture inoculation, and fermentation with variations in time of 0, 3, 4, 5, 6, and 7 days using 3% sucrose (w/v). The results showed that fermentation time had a significant effect on citric acid concentration and yield. At 0 days, citric acid had not yet formed because the fermentation process had not yet begun. Optimal conditions were obtained on day 3 with a pH of 2, a density of 1.19 g/mL, a total acidity of 0.23, and a yield of 37%. On day 4, although total acid increased to 1.60 g/mL, the yield decreased to 18% due to overly acidic conditions (pH 0) that inhibited the enzymatic activity of Aspergillus niger. Thus, fermentation for three days is the optimum condition for efficiently producing citric acid through solid fermentation using Aspergillus niger.

Kata kunci

• asam sitrat
• Citrus reticulata
• fermentasi padat
• Aspergillus niger