Optimization of the production of Weissella confusa MBF8-1 lysate in plant-based media by using response surface methodology

Aims@#Bacterial lysate has been reported to possess many health-care-related benefits. This study aimed to determine the optimum conditions for producing Weissella confusa MBF8-1 lysate in two plant-based modified De Man, Rogosa, and Sharpe (MRS) media using the response surface methodology (RSM). In this study, we applied several condition factors and compared them to standard MRS media. @*Methodology and results@#Weissella confusa MBF8-1 was grown in two modified MRS media, which are MRS Vegitone and soy peptone modified-MRS. The optimized fermentation condition factors such as nitrogen sources (i.e., soy peptone, proteose peptone), dextrose concentrations, and fermentation time were measured, and the responses, such as bacteriocin-like inhibitory substance (BLIS) activity and lysate pH were observed. RSM results showed the diameter of BLIS activity-inhibition zone and pH decreases of the lysate produced in MRS Vegitone containing 1.50% dextrose, 0.75% proteose peptone for 11.75 h fermentation and in soy peptone modified-MRS containing 2.05% dextrose, 1.05% soy peptone for 7.53 h fermentation, i.e., 7.41 mm at 7.36, and 7.80 mm at 7.30, respectively. Whereas, lysate produced in standard MRS medium containing 2% dextrose, 1% peptone for 8 h fermentation showed 7.85 mm diameter of BLIS activity-inhibition zone at pH 7.26. W. confusa MBF8-1 lysate showed slightly lower pH, but higher BLIS activity when grown in standard MRS media compared to those of the two modified MRS media. @*Conclusion, significance and impact of study@#The data obtained provide the optimum condition of W. confusa MBF8-1 lysate production in plant-based media. The pH and BLIS activity possessed by W. confusa MBF8-1 lysate produced in soy peptone modified-MRS showed a more similar result as the standard one than the other modified one. Thus, the soy peptone modified-MRS is recommended as a plant-based alternative medium replacing standard MRS.

Identification and characterization of three endophytic bacteria from Neesia altissima (Malvaceae) antagonistic to diarrhea-causing bacteria

Aims: Diarrheal disease is one of serious healthcare problems in developing countries. Endophytic bacteria have been known as a promising source of new antibiotics against susceptible and resistant forms of microorganisms. In this study, we identified three endophytic bacteria isolated from Neesia altissima and screened their antagonistic activity against diarrhea-causing bacteria in order to find new potential secondary metabolites. Methodology and results: Samples of N. altissima were collected from mount Halimun-Salak national park. Endophytic bacteria were isolated from roots, barks, and fresh leaves of N. altissima by surface sterilized method. Screening of antagonistics activity was conducted against five diarrhea-causing bacteria such as Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Shigella flexneri, and Bacillus cereus using crude extract dilution and diffusion disc methods. Three endophytic bacteria showed antagonistic activity against the pathogenic bacteria. Identification of the three potential endophytic bacteria using molecular analysis showed that two isolates determined as Pseudomonas aeruginosa and one isolate belongs to P. azotoformans. Conclusion, significance and impact study: Crude extract of P. aeruginosa (strain 1.4.1A and 1.2.7D) and P. azotoformans (strain 1.8.7KB) showed growth inhibition activity to the diarrhea-causing bacteria. This is the first report of P. azotoformans exhibited antagonistic activities against diarrhea-causing bacteria. This data suggested that bacterial endophytes from N. altissima provided potential sources for the discovery of new secondary metabolites to combat the diarrhea-causing bacteria. This finding highlights potential prospects of endophytic bacteria utilization from endemic medicinal plants for the discovery of novel bioactive compounds.

Optimization of submerged culture for biomass and polysaccaharide of Pleurotus ostreatus BPPTCC 6017 using response surface methodology

Aims: Polysaccharide of Pleurotus ostreatus is one of the fungal polysaccharide which has been widely studied, produced by extracting the fruiting body. An alternative method for producing polysaccharide of P. ostreatus directly from the mycelia instead of the fruiting body is through submerged culture. This study was aimed to determine the optimum submerged culture conditions for producing biomass and intracellular polysaccharide of the oyster mushroom. Methodology and results: P. ostreatus BPPTCC 6017 was collected from traditional mushroom farm in West Java, Indonesia. Submerged fermentation was conducted in 1000 mL medium (2 L flask). Four variables were tested: temperature, pH, agitation, and fermentation time, using central composite design of the response surface methodology. Mycelial biomass produced, was extracted to obtain water-soluble and alkali-soluble polysaccharide. Experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analysed by appropriate statistical methods. The 3-D response surface plots derived from the mathematical models were applied to determine the optimum conditions: temperature 27.89 °C, initial pH medium 5.49, agitation 124.08 rpm, and fermentation time 11.44 days. The predicted results of the models were 33.75 g/L mycelia, 0.33 g/L water-soluble polysaccharide, and 0.64 g/L alkali-soluble polysaccharide. Those results were then verified on the optimum conditions, and produced 32.00±1.25 g/L mycelia, 0.29±0.01 g/L water-soluble polysaccharide and 0.60±0.02 g/L alkali-soluble polysaccharide, were close to the theoretical predictions. Conclusion, significance and impact study: The present study was a first effort to assess and obtain the optimum conditions for producing the biomass and polysaccharides of the strain P. ostreatus BPPTCC 6017 using submerged fermentation

Screening Cellulose Activity of Yeast Isolated from Soil, Sediment and Water River from Taman Nasional Gunung Halimun, West Java, Indonesia

A total of 245 yeast isolates from Gunung Halimun National Park (GHNP) were screened for cellulolytic activity using 0.2% cellulose-azure. The results showed that 16 isolates have cellulolytic activity using cellulose-azure assay. These isolates were further screened for carboxymethyl cellulase (CMCase), avicelase and cellobiase using specific substrates (carboxymethyl cellulosa, avicel and cellobiose) with Teather and Wood method. The results showed that 7 isolates have CMCase; 6 isolates have cellobiase; 2 isolates have CMCase and cellobiase; and 1 isolate has CMCase and avicelase and cellobiase activities. Isolate S 4121 has the highest CMCase activity and identified as Trichosporon sporotrichoides (van Oorschot) van Oorschot and de Hoog UICC Y-286.