Megabiodiversity of Malaysian’s flora and fauna which include microorganism could be conserved and served as alternative source indigenous yeast, the leavening agent of commercial bread making. This study was conducted in attempt to exploit the potential of Saccharomyces cerevisiae strains isolated from 30 different local fruits and plant parts as a leavening agent in bread making. The enrichment was carried out by fermenting the plant samples in medium containing Grape Must at 25°C for 10 days following by isolation of tentative yeasts at 30°C for 3 to 5 days. 20 out of 30 samples tested showed the presence of yeasts was then selected for identification of S. cerevisiae strains through biochemical and physiological tests. Of the 20 yeast strains examined, 13 strains were identified as S. cerevisiae and potentially used as leavening agent in bread making where 5 strains namely SN3, SMK9, SDB10, SRB11 and SS12 showed better fermentative performance compared to commercial strains. Thus, indicated that the local fruits and plant parts could be the potential source of indigenous S. cerevisiae strains for leavening agent in bread making.
Catheter-related bloodstream infections caused by Kodamaea ohmeri are generally not considered due to the relative scarcity of reported cases. This is a case of an 85-year-old man with poorly controlled diabetes mellitus who was initially admitted to our hospital for diabetic ketoacidosis. An internal jugular catheter was inserted as part of the initial management. A week later the patient developed a temperature spike and a yeast identified as Kodamaea ohmeri by ID 32 C (bioMérieux, France) was isolated from both his central and peripheral blood cultures. The catheter was removed and the patient was treated with fluconazole despite the organism’s relatively high minimum inhibitory concentration (2 μg/mL) to this antifungal. The fungemia resolved following a 2-weeks course of fluconazole.
Despite the advantages of continuous fermentation whereby ethanol is selectively removed from the fermenting broth to reduce the end-product inhibition, this process can concentrate minor secondary products to the point where they become toxic to the yeast. This study aims to develop a new mathematical model do describe the inhibitory effect of byproducts on alcoholic fermentation including glycerol, lactic acid, acetic acid, and succinic acid, which were reported as major byproducts during batch alcoholic fermentation. The accumulation of these byproducts during the different stages of batch fermentation has been quantified. The yields of total byproducts, glycerol, acetic acid, and succinic acid per gram of glucose were 0.0442, 0.023, 0.0155, and 0.0054, respectively. It was found that the concentration of these byproducts linearly increases with the increase in glucose concentration in the range of 25-250 g/L. The results have also showed that byproduct concentration has a significant inhibitory effect on specific growth coefficient (μ) whereas no effect was observed on the half-velocity constant (Ks). A new mathematical model of alcoholic fermentation was developed considering the byproduct inhibitory effect, which showed a good performance and more accuracy compared to the classical Monod model.