OPTIMIZATION OF BIOCONVERSION OF WASTE COCONUT WATER TO ACETIC ACID

• Main Author: Enar, Rohmala
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/35658
• Institution: Institut Teknologi Bandung

NIM : 20507059 Coconut water has sugar-content of 2.08 mg/l00g that was used as a raw material for acetic acid production. Coconut water that thrown away is a good source for environment pollution, since its Biological Oxygen Demand (BOD) around 40.000 mg/l. An attempt was made to reduce environment pollutant by transforming coconut water to acetic acid. This experiment can be used as a model to study the reaction in carbohydrate biotransformation. Two culture types were chosen as a starter that were Saccharomyces cerevisiae (laboratory [?LE2(803)] and market) and kamboucha. Research steps involved were activation of innoculums, fermentation, distillation and characterization of distillate by determination of pH, color, aroma, qualitative test of acetic acid and total concentration of acetic acid. Inoculums activation for S. cerevisiae (laboratory and market) was conducted in YEPD solid media. Then a single colony was subcultured to YEPD liquid media. Incubation was conducted at 30°C, 150 rpm for 2 x 24 hours. Herein sub sample was made to 3 types of liquid media coconut water that were coconut water and dilute coconut milk (AK-S), coconut water containing 1 % (w/v) peptone (AK-P) and 10 % (v/v) coconut water in water (AK 10%). Incubation was conducted at 30°C, 150 rpm for 2 x 24 hours. To adapt yeast in media of coconut water, activation was also conducted at room temperature, 150 rpm for 2 x 24 hours. Kamboucha was growth in coconut water 10 % . Kamboucha B 10 % (v/v) was prepared by inoculums kamboucha A. For further experiment 10% (v/v) coconut water in water (AK 10%) was chosen as a stock culture for fermentation media. Fermentation media consist of 0,3 % (w/v) urea, 0,8 % (w/v) ammonium phosphate and 5 % (w/v) sugar. Afterwards to process ferment was used yeast media in coconut water 10 % (AK 10%). Aerobic fermentation was conducted for 7 x 24 hours at room temperature. Fermentation process were conducted in two kinds of condition that was continuous shaking [?LE2(803)cont and marketcont] and shaking every 12 hours [?LE2(803)12hr and market12hr]. Fermentation using ?LE2(803) in a continuous shaking reactor the pH of the mixture from 7.35 to 4.71 while those with market yeast to 6.37. For those that shaked every 12 hours, ?LE2(803) decrease the pH of the mixture to 4.05, while those with market yeast reduced the pH to 6.07. Whilst kamboucha A and B decreased the pH of the mixture to 5.11 and 5.86 respectively. The fermentation product was distilled and fraction < 75oC and 98oC were collected separately. The pH of fraction < 75oC of those fermented by ?LE2(803)cont, ?LE2(803)12 hr, marketcont, market12 hr, Kamboucha A and Kamboucha B were 5,13; 8,70; 9,05; 8,44; 8,26 and 8,21 respectively. Whereas pH of fraction 98oC were 3,39; 4,09; 5,43; 4,19; 3,71 and 2,81. Acid distillates were subjected to the organoleptic test for ethyl acetate aroma. The results showed all of the samples have aroma was less fragrant. The average score were 1,5; 1,5; 1,9; 1,5; 1;6 and 1,9; for ?LE2(803)cont, ?LE2(803)12 hr, market cont, market12 hr, Kamboucha A and Kamboucha B respectively. Qualitative test for acetic acid all of the samples showed positive result as red-brown precipitate performed which is complex innoculum between iron and acetate ion. The yield of acetic acid biotransformation was confirmed by total acetic acid assay. The result showed that the yield for ?LE2(803)cont, ?LE2(803)12 hr, marketcont, market12hr, Kamboucha A and Kamboucha B were 0.327 M, 0.079 M, 0.130 M, 0,162 M, 0.392 M and 0.242 M respectively. This result showed that ?LE2(803) and Kamboucha A were the best culture for acetic acid biotransformation.