Combined treatment of landfill leachate with fecal supernatant in sequencing batch reactor

A laboratory-scale sequencing batch reactor (SBR) is used to treat landfill leachate containing high concentration of ammonium nitrogen with municipal fecal supernatant. The SBR system is operated in the following sequential phases: fill period, anoxic period, aeration period, settling period, decant and idle period. The results indicated that the average removal efficiencies of COD, BOD5, TN, NH 4+-N were 93.76%, 98.28%, 84.74% and 99.21%, respectively. The average sludge removal loading rates of COD, BOD5, TN and NH 4+-N were 0.24 kg/(kg SS?d), 0.08 kg/(kg SS?d), 0.04 kg/(kg SS?d) and 0.036 kg/(kg SS?d), respectively. Highly effective simultaneous nitrification and denitrification was achieved in the SBR system. The ratio of nitrification and denitrification was 99% and 84%, respectively. There was partial NO?2 denitrification in the system.

Enhancing the culturability of bacteria from the gastrointestinal tract of farmed adult turbot Scophthalmus maximus

Eighteen agar media were tested for the culture of gut-associated bacteria from farmed adult turbot （Scophthalmus maximus）, including 16 agar media with or without 1% gastrointestinal （GI） supernatant, or with 2% or 4% GI supernatant. A total of 1 711 colonies were analyzed and 24 operational taxonomic units （OTUs） were identified. The greatest bacterial diversity was isolated on Zobell 2216E/ Zobell 2216E＋ agar media, whereas MRS/MRS＋ agar media produced a low diversity of colonies, Agar media with GI supernatant （1%, 2%, or 4%） showed increased diversity and yielded different profiles of OTUs from the corresponding original media, suggesting that GI supernatant provides substances that enhance the culture efficiency of bacteria from the turbot GI tract. The large majority of the colonies （82%） were 7-Proteobacteria, whereas 15.6% and 2.4% of colonies were Firmicutes and Actinobacteria, respectively. At the genus level, 49.4% of all colonies were assigned to Vibrio. Other potential pathogens, including Pseudomonas, Photobacterium, and Enterobacter, and potential probiotics, including Bacillus, Paenibacillus, and Pseudomonas, were also isolated on agar media. Most cultured bacteria belonged to species that were first described in the turbot GI tract. The impact of these species on turbot physiology and health should be investigated further.

Acaricidal activities of whole cell suspension,cell-free supernatant,and crude cell extract of Xenorhabdus stokiae against mushroom mite (Luciaphorus sp.)

Xenorhabdus bacterium has been used as a biological control agent against Luciaphorus sp., a mushroom mite endemic in Thailand. To develop an effective formulation ofXenorhabdus stokiae, treatments using different parts of X. stokiae isolate PB09 culture, including whole cell suspension, cell-free supernatant, and crude cell extract, were performed. The results show that different parts ofX. stokiae isolate PB09 culture could induce variable effects on mite mortality and fecundity. Application with cell-free supernatant of X. stokiae culture resulted in both the highest mite mortality rate [（89.00＋3.60）%] and the lowest mite fecundity [（41.33_＋23.69） eggs/gravid female]. Whole cell suspen- sion of X. stokiae isolate PB09 culture was found to be slightly less effective than its cell-free supernatant, suggesting that X. stokiae was more likely to release its metabolites with acaricidal activities to the surrounding culture media. Crude cell extract of X. stokiae was not effective against mites. Cell-free supematant of X. stokiae isolate PB09 was the most effective biological control agent and it could be conveniently used in future formulations instead of live bacteria.