Microbial succession in a fermenting of wild forest noni ( Morinda coreia Ham) fruit plus molasses and its role in producing a liquid fertilizer

The numbers of lactic acid bacteria (LAB) and yeasts that were present during a wild forest noni ( Morinda coreia Ham) fermentation, the changes in its physico-chemical properties and levels of plant nutrients were investigated. LAB increased rapidly during the first 7 days and were the dominant population until after day 21 when the LAB were declining and the yeasts began to dominate. Identification of the LAB and yeasts to species level showed that the dominant LAB throughout was Lactobacillus plantarum while Lactobacillus pentosus was found but only at day 21. Saccharomyces cerevisiae was the most dominant species of yeast throughout but was slowly replaced by Pichia membranifaciens and then Pichia anomala . Rhodotolura mucilaginosa , an aerobic yeast, was only detected at the beginning of the fermentation process. It is suggested that the Pichia spp. were responsible for consuming lactic acid. After 56 days, the values of pH, acetic acid, ethanol and electrical conductivity in the fermented product were 3.66, 3.34 g L-1, 16.98 g L-1 and 14.47 mS cm-1, respectively. Increased amounts of plant nutrients were present at day 56 mostly derived from the degradation of plant material. At day 56 the amounts were as follows (in mg L-1): N 633, P 1210, K 4356, Ca 693, Mg 536, Mn 7, B 51, Zn 169, and total carbon/total nitrogen ratio (C/N ratio) 18. Based on the seed germination index (GI) of cherry tomato ( Lycopersicon esculentum Mill), the extract diluted 256-fold gave the best GI of 157%

Selection of sulfur oxidizing bacterium for sulfide removal in sulfate rich wastewater to enhance biogas production

Sulfur oxidizing bacteria (SOB) were isolated and tested in order to remove sulfide from high sulfate wastewater to reduce the amount of hydrogen sulfide (H2S) in the produced biogas. A promising SOB isolate, designated as isolate T307, was selected due to its best sulfide removal (86.7%) in the effluent of a sulfate reduction reactor (SRR) over a 24 hrs incubation. The bacterium was able to grow better as a mixotroph (yeast extract as a carbon source) than as a chemolithoautotroph. In addition, as a heterotroph, the bacterium grew well with yeast extract and peptone. Based on partial 16S rRNA gene sequence, the isolated T307 was an Alcaligenes sp. and was able to convert most of sulfide species (total sulfide: TS; dissolved sulfide: DS and H2S) into elemental sulfur or sulfate over a 20 hrs period of cultivation by controlling the speed of shaking. In a biogas reactor set, after pre-treating a sulfide medium with Alcaligenes sp. T307 there was a much higher specific yield of CH4 (238 ml CH4 g-1COD removed) and more biogas (154 ml L-1 d-1) was produced with the biogas containing more methane (48.1% CH4, 51.5% CO2 and 0.41% H2S) in comparison to a control with a specific yield of CH4, (72 ml CH4 g-1COD removed) 86 ml L-1 d-1 biogas produced with a composition of 35.5% CH4, 63.7% CO2 and 0.86% H2S

Inhibition of shrimp pathogenic vibrios by extracellular compounds from a proteolytic bacterium Pseudomonas sp. W3

Pseudomonas sp. W3, a bacterium known to produce an extracellular alkaline protease, secreted secondary metabolites that inhibited pathogenic bacteria responsible for shrimp luminous vibriosis disease. Antivibrio compounds in the culture supernatant or culture filtrates (0.45 \ub5m and 0.22 \ub5m) of the isolate W3 were tested using an agar well diffusion method on a number of pathogenic vibrios. Vibrio harveyi PSU 2015 a pathogenic isolate was the most sensitive strain. The effectiveness of preparations from the isolate W3 against V. harveyi PSU 2015, and V. cholerae PSSCMI 0062 was in the order of culture supernatant > 0.45 \ub5m culture filtrate > 0.22 \ub5m culture filtrate. These extracellular antivibrio compounds also lysed both dead and living cells of V. harveyi PSU 2015. Results of the partial characterization tests indicated that there was some particulate antivibrio compound that was destroyed by treatment with enzymes particularly \u3b1-chymotrypsin, autoclaving at 121\ubaC for 15 min and was mostly removed by filtration through a 0.22 \ub5m filter. Most of the inhibitory compounds were of small molecular weight able to pass through a 0.22 \ub5m filter and were resistant to treatment with various enzymes, pH values between 4-8 and temperatures up to 121\ubaC for 30 min. The optimum pH for the antivibrio activity in the 0.45 \ub5m culture filtrate was between pH 6-7

Characteristics of fermented plant beverages in southern Thailand

The characteristics of fermented plant beverages based on a sensory test, physico-chemical properties, enumeration of microorganisms present and their microbiological quality were investigated. A total of 19 samples of beverages collected from various sources in southern Thailand were examined. It was found that odor, color and clarity and the presence of Cu, Zn, K and Na were mainly dependent on the types of plant used and the additive of sugar or honey. Therefore, the appearance of the beverages was light brown and dark brown. An ester smell was occasionally detected. The fermented plant beverages had sour flavor that developed during fermentation and a little sweetness from residual sugar. The taste was related to the amounts of organic acid and sugar as measured in the ranges of 0.98-7.13% (pH 2.63-3.72) and 0.21-4.20%, respectively. The levels of alcohols measured as ethanol were between 0.03-3.32% and methanol in a range of 0.019 0.084%. Methanol production was dependent on both the fermentation process and the plant used. Total coliforms and Escherichia coli were not detected in any sample, whereas other microbes were detected in some samples as were total bacterial count, lactic acid bacteria, yeast and mold in amounts that differed depending on the fermentation time and also the level of sanitation of the production process

Selection of proteolytic bacteria with ability to inhibit Vibrio harveyi during white shrimp (Litopenaeus vannamei) cultivation

Five isolates of bacteria with high proteolytic activity, isolated from water samples of intensive shrimp ponds in southern Thailand, were selected to test for the ability to control the shrimp pathogen Vibrioharveyi. 70 μl of each culture broth were investigated for their ability to inhibit V. harveyi using an agar well diffusion test but only one isolate W3 gave a reasonable sized inhibition zone of 21.62 mm. This zone wassimilar to that of oxolinic acid (2 μg) and sulfamethoxazole (25 μg). The W3 isolate was identified as Pseudomonas sp. Shrimp cultivation in aquaria was conducted to investigate the inhibition of V. harveyi bythe isolate W3. The experiment consisted of a treatment of the shrimp culture with an inoculum of the isolate W3 and V. harveyi (biocontrol set), a positive control set (only inoculation of V. harveyi) and a negativecontrol set as without inoculation. No mortality was found in the negative control. Shrimp mortality in the biocontrol set (33%) was lower than that in the positive control set (40%); however, it showed no significantdifference (p>0.05). The average numbers of V. harveyi over 12 days of the biocontrol set were lower than those in the positive control set by about 1 log cycle although the numbers were not significantly different(p>0.05). The shrimp growth rate at day 32 of cultivation was in order of the biocontrol treatment (10.17%) > the negative control treatment (9.44%) > the positive control set (9.28%), but no significant difference (p>0.05) was observed among treatments

Screening of probiotic lactic acid bacteria from Thai fermented foods for human.

Total of 327 strains of lactic acid bacteria were isolated from 179 samples of various Thai fermented foods. The strains were investigated for their probiotic properties based on stability in bile salt (0.15%) and high acidity (pH 2, 3 and 4). Moreover, utilization of protein or fat or starch, growth in the absence of vitamin B12 and growth under both aerobic and anaerobic conditions with no significant difference were also considered. According to the above criteria, 67 strains were selected for antibiotics sensitivity test. The selected strains were susceptible to following antibiotics: ampicillin, cephalothin, cefoperazone, tetracycline andchloramphenicol; however the strains were resistant to vancomycin, kanamycin, streptomycin, norfloxacin and polymyxin B. Using agar spot method, only 5 strains were able to inhibit 13 strains of manifest by a bacteria indicator as clear zone greater than 10 mm. A further investigation using co-culture technique showed inhibition of the tested organisms was between 80 and 100 percent. The strains grew under media of MRS and SPY2 (no materials from animal) over 36 hours with no significant difference. The strains were investigated for survival in condition of high acidity within 3 hours. It was found that at pH 4 almost 100% were maintained but at pH 2 and 3 the survival reduced approximately 1 log cycle. The strain LA71 which showed the highest survival was identified as Lactobacillus plantarum

Sanitation conditions of clean food good taste restaurants in Hat Yai City Municipality

Sanitation conditions and microbiological quality of 52 “Clean Food Good Taste” restaurants in Hat Yai city municipality were examined using a standard food sanitation survey checklist based on the Department of Health and Department of Medical Science, Ministry of Public Health. Coliform bacteria and Escherichia coli (E. coli) were investigated in samples of foods and drinking water, whereas total bacterial count (TBC) was carried out in samples of foods, plates, spoons, glasses and food handlers. The methods of investigation were the Most Probable Number (MPN) method for coliform bacteria, E. coli and the standard plate count method for TBC. The SI-2 field test kit was used to indicate microbiological contamination, particularly coliform bacteria. It was found that 38/52 (73.1%) restaurants passed all items of food sanitation standard. The food sanitation condition with the lowest number passing was the dressing of food handlers (45/52, 86.5%) followed by the area for eating, preparing and cooking (47/52, 90.4%). Microbiological quality of food samples based on both MPN of coliform bacteria and E. coli was at an acceptable level in 190/202 samples (94.1%). However, in samples of drinking water only 19/52 (36.5%) passed the MPN standard for coliform bacteria and 45/52 (86.5%) that for E. coli. Moreover, among the 52 restaurants, the numbers (percentages) passing the standard TBC in samples of plate, spoon, glass, cooker handlers and server handlers were 32 (61.5%), 27(51.9%), 20 (38.5%), 2 (3.9%) and 1 (1.9%), respectively. Comparison of microbiological quality between the SI-2 test kit and MPN coliform/TBC showed no significant differences for samples of foods, but significant differences for the rest of the samples (p<0.05, t-test)

Effects of long-term contamination of DDT on soil microflora with special reference to soil algae and algal transformation of DDT

DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) and its principle metabolites, DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) and DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane) are widespread environmental contaminants but little information is available concerning their effects on non-target microflora (especially microalgae and cyanobacteria) and their activities in long-term contaminated soils. For this reason a long-term DDT-contaminated soil was screened for DDT residues and toxicity to microorganisms (bacteria, fungi, algae), microbial biomass and dehydrogenase activity. Also, five pure cultures isolated from various sites (two unicellular green algae and three dinitrogen-fixing cyanobacteria) were tested for their ability to metabolise DDT. Viable counts of bacteria and algae declined with increasing DDT contamination while fungal counts, microbial biomass and dehydrogenase activity increased in medium-level contaminated soil (27 mg DDT residues kg?1 soil). All the tested parameters were greatly inhibited in high-level contaminated soil (34 mg DDT residues kg?1 soil). Species composition of algae and cyanobacteria was altered in contaminated soils and sensitive species were eliminated in the medium and high contaminated soils suggesting that these organisms could be useful as bioindicators of pollution. Microbial biomass and dehydrogenase activity may not serve as good bioindicators of pollution since these parameters were potentially influenced by the increase in fungal (probably DDT resistant) counts. All the tested algal species metabolised DDT to DDE and DDD; however, transformation to DDD was more significant in the case of dinitrogen-fixing cyanobacteria