Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
Among twenty one isolates, obtained from "aren" (Aretga Rinnata) vinegar, 10 isolates were identified as acetic acid bacteria, belong to genus Acetobacter. Isolates no. 12 was used as inoculum for vinegar fermentation. Saccharomyces cerevisiae (Y-17) was provided by University of Indonesia Culture Collection. Two hundred fifty grams of pineapple (Ananas comosus) peel was boiled for 1.5 hours and then filtered to obtain the extract. Aquadest was added into substrate to obtain 1 litre of extract and then added with 15% or 20% castor sugar. Substrate was sterilised at 121°C for 10 minutes. Fermentation was carried out in syrup bottle containing 540 ml substrate. Approximately 60 ml of starter containing mix-culture with diffrent ratio of 1 day old S. cer visiae (106 cfu/ml) and 5 days old Acetobacter sp. no.12 {10 cfu/ml) was inoculated into the substrate. The ratio of yeast cells to bacteria were follow: (1:1); (2:1); (3:1} or (4:1). Fermentation was set up in room temperature (3O -- 32°C for 1 month. The concentration of acetic acid was titrated with standarised NaOH. Result of this study showed that substrate with 15% sugar yielded (1.1 - 1.4)% acetic acid. The average acetic acid concentration from substrate with 20% sugar were (0.44 - 0.89%). It was concluded that substrate with 15% sugar gave higher concentration and the best ratio of starter was (1 : 1).

Abstrak :
ABSTRAK
This study aims to investigate the feasibility of using a minimal glycerol medium with inorganic salt supplementation for a low-cost dihydroxyacetone (DHA) production by bacteria. Acetic acid bacterial isolates of Gluconobacter and Asaia, which are found in the Northern, North-Eastern, Middle, Western, and Southern regions of Thailand, were evaluated for their ability to produce DHA using glycerol as a carbon source. During the qualitative screening, 66 isolates, including Gluconobacter (61 isolates) and Asaia (5 isolates), from a total of 486 isolates showed highly positive results by the Fehling test. The 5 isolates of Asaia gave low DHA production in the quantitative screening, whereas Gluconobacter isolates showed DHA production at low (0-5.70 g/L), medium (5.71-11.40 g/L), and high (11.41-16.89 g/L) levels. Preliminary culture medium optimizations for G. frateurii BCC 36199, a most promising microorganism for DHA production, were also carried out using a low-cost minimal glycerol medium supplemented with an inorganic salt. G. frateurii BCC 36199 produced 18.67 g/L of DHA with ysp of 95.44% (DHA moles/glycerol moles) at 30°C, 20 g/L of glycerol, and pH 4.5. The cultivation of G. frateurii BCC 36199 in the developed minimal glycerol medium is practical and can be further optimized in order to apply for industry.