[Treatment of Simulated Saline Wastewater from the Coal Chemical Industry Using Ecological Floating Beds Enhanced with Arbuscular Mycorrhiza].

For the problem that few technologies can be directly used to treat wastewater with middle and low salt, in this study, arbuscular mycorrhizal (AM) fungi were used to enhance the tolerance of wetland plants to salt stress. Ecological floating beds (EFBs) enhanced with AM fungi were constructed to explore a new technology as well as to treat wastewater with low and medium salt content, but also to overcome the low tolerance to salt stress and low salt removal by EFB plants. Results showed that canna plants (Canna indica L.) were well colonized by AM fungi (Glomus etunicatum) and the mycorrhizal colonization rate was not affected by salt stress. Inoculation with AM fungi enhanced the ability of the EFBs to treat saline wastewater. After treatment by EFB with AM for 21 d, removal rates of total dissolved solids (TDS), chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were 36.1%, 74.4%, 57.6%, and 59.1%, respectively, which were higher by 79.2%, 36.4%, 32.7%, and 37.6% over those with treatment by EFB without AM, respectively. Removal rates of Na, K, Ca, and Mg were 34.4%, 61.3%, 57.4%, and 51.9% after 21 d of treatment by EFB with AM, which were higher by 11.4%, 37.1%, 18.3%, and 24.6%, respectively, than removal rates with treatment by EFB without AM, respectively. Plant sample analysis showed that AM increased the Na uptake of plants and Na transportation from root to shoot, and this may be the reason that AM enhanced the ability of the EFBs to treat saline wastewater. This study indicated that AM fungi can be used to improve the ability of EFB to remedy water pollution and increase salt removal efficiency.

Biodegradation of di-n-butyl phthalate (DBP) by a novel endophytic Bacillus megaterium strain YJB3.

Phthalic acid esters (PAEs) are a group of recalcitrant and hazardous organic compounds that pose a great threat to both ecosystem and human beings. A novel endophytic strain YJB3 that could utilize a wide range of PAEs as the sole carbon and energy sources for cell growth was isolated from Canna indica root tissue. It was identified as Bacillus megaterium based on morphological characteristics and 16S rDNA sequence homology analysis. The degradation capability of the strain YJB3 was investigated by incubation in mineral salt medium containing di-n-butyl-phthalate (DBP), one of important PAEs under different environmental conditions, showing 82.5% of the DBP removal in 5days of incubation under the optimum conditions (acetate 1.2g·L-1, inocula 1.8%, and temperature 34.2°C) achieved by two-step sequential optimization technologies. The DBP metabolites including mono-butyl phthalate (MBP), phthalic acid (PA), protocatechuic acid (PCA), etc. were determined by GC-MS. The PCA catabolic genes responsible for the aromatic ring cleavage of PCA in the strain YJB3 were excavated by whole-genome sequencing. Thus, a degradation pathway of DBP by the strain YJB3 was proposed that MBP was formed, followed by PA, and then the intermediates were further utilized till complete degradation. To our knowledge, this is the first study to show the biodegradation of PAEs using endophyte. The results in the present study suggest that the strain YJB3 is greatly promising to act as a competent inoculum in removal of PAEs in both soils and crops.

Effects of Funnelliformis mosseae inoculation on alleviating atrazine damage in Canna indica L. var. flava Roxb.

Atrazine residue in the environment continually damages plants and therefore requires immediate attention and effective development of methods for its decontamination. The effects of Funnelliformis mosseae inoculation on growth and physiology in atrazine-treated Canna indica L. var. flava Roxb. were investigated. At atrazine concentrations up to 15 mg L-1, the growth of C. indica plants were negatively affected. Inoculation with F. mosseae alleviated the atrazine inhibition of plant growth and biomass. Furthermore, the chlorophyll content and root function increased under F. mosseae inoculation, and the oxidative stress of malondialdehyde, peroxidase, and superoxide dismutase activities induced by atrazine were also alleviated by F. mosseae inoculation. The removal rate of atrazine by untreated C. indica was significant, with removal rates of 20.5-55.3% by the end of a 14-day experiment; however, F. mosseae inoculation increased the removal rate to 35.6-75.1%. In conclusion, F. mosseae inoculation can alleviate the damage induced by atrazine in C. indica. Accordingly, C. indica inoculated with F. mosseae has excellent potential to be used in phytoremediation in habitats polluted by high atrazine concentrations.

Simultaneous utilization of non-starch polysaccharides and starch and viscosity reduction for bioethanol fermentation from fresh Canna edulis Ker. tubers.

Viscosity reduction and the effect of cell-wall degrading enzymes (CWDEs) were investigated using Canna edulis Ker. for bioethanol fermentation. The fermentation mash treated with CWDEs was much thinner (2.12 Pas) than the control mash (8.42 Pas), the fermentation efficiency was increased from 90.46% to 96.11%. HPLC analysis revealed that after treated with CWDEs, glucose and total sugar were increased by 28.07% and 7.60%, respectively. Changes in the starch granules were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and confocal laser scanning microscopy (CLSM). The results suggested that the reduction in viscosity was caused by changes in saccharide composition and physical changes of the starch granules. This present study is of significance that non-starch polysaccharides and starch can be simultaneously utilized for bioethanol production using roots and tubers as feedstock.

Isolation and characterization of polymeric galloyl-ester-degrading bacteria from a tannery discharge place.

The culturable bacteria colonizing the rhizosphere of plants growing in the area of discharge of a tannery effluent were characterized. Relative proportions of aerobic, denitrifying, and sulfate-reducing bacteria were determined in the rhizosphere of Typha latifolia, Canna indica, and Phragmites australis. Aerobic bacteria were observed to be the most abundant group in the rhizosphere, and plant type did not seem to influence the abundance of the bacterial types analyzed. To isolate bacteria able to degrade polyphenols used in the tannery industry, enrichments were conducted under different conditions. Bacterial cultures were enriched with individual polyphenols (tannins Tara, Quebracho, or Mimosa) or with an undefined mixture of tannins present in the tannery effluent as carbon source. Cultures enriched with the effluent or Tara tannin were able to degrade tannic acid. Six bacterial isolates purified from these mixed cultures were able to use tannic acid as a sole carbon source in axenic culture. On the basis of 16S ribosomal DNA sequence analysis, these isolates were closely related to organisms belonging to the taxa Serratia, Stenotrophomonas maltophilia, Klebsiella oxytoca, Herbaspirillum chlorophenolicum, and Pseudomonas putida.

16S ribosomal DNA characterization of nitrogen-fixing bacteria isolated from banana (Musa spp.) and pineapple (Ananas comosus (L.) Merril).

Nitrogen-fixing bacteria isolated from banana (Musa spp.) and pineapple (Ananas comosus (L.) Merril) were characterized by amplified 16S ribosomal DNA restriction analysis and 16S rRNA sequence analysis. Herbaspirillum seropedicae, Herbaspirillum rubrisubalbicans, Burkholderia brasilensis, and Burkholderia tropicalis were identified. Eight other types were placed in close proximity to these genera and other alpha and beta Proteobacteria.

Development of a transformation system for Mycosphaerella pathogens of banana: a tool for the study of host/pathogen interactions.

A genetic transformation system has been developed for three Mycosphaerella pathogens of banana and plantain (Musa spp.). Mycosphaerella fijiensis and Mycosphaerella musicola, the causal agents of black and yellow Sigatoka, respectively, and Mycosphaerella eumusae, which causes Septoria leaf spot of banana, were transformed with a construct carrying a synthetic gene encoding green fluorescent protein (GFP). Most single-spored transformants that expressed GFP constitutively were mitotically stable in the absence of selection for hygromycin B resistance. Transformants of all three species were pathogenic on the susceptible banana cultivar Grand Nain, and growth in planta was comparable to wild-type strains. GFP expression by transformants allowed us to observe extensive fungal growth within leaf tissue that eventually turned necrotic, at which point the fungi grew saprophytically on the dead tissue. Leaf chlorosis and necrosis were often observed in advance of saprophytic growth of the mycelium on necrotic tissue, which supports previous reports suggesting secretion of a phytotoxin.

Evaluation of numerical analyses of RAPD and API 50 CH patterns to differentiate Lactobacillus plantarum, Lact. fermentum, Lact. rhamnosus, Lact. sake, Lact. parabuchneri, Lact. gallinarum, Lact. casei, Weissella minor and related taxa isolated from kocho and tef.

AIM: The study was carried out to assess the agreement of API 50 CH fermentation data of food lactobacilli with their RAPD profiles to determine whether the system could be used alone as a reliable taxonomic tool for this genus. METHODS AND RESULTS: API 50 CH, RAPD and DNA:DNA reassociation data for 42 lactobacilli from tef and kocho were compared with 30 type strains. Discrepancies were observed between the three methods in assigning strains of Lactobacillus plantarum, Lact. fermentum, Weissella minor and Lact. gallinarum, and Lact. fermentum, Lact. amylophilus, Lact. casei subsp. pseudoplantarum and Lact. rhamnosus. DNA reassociation data agreed well with RAPD results. CONCLUSIONS: API 50 CH profiles should be complemented with molecular genetic results for effective identification in Lactobacillus. SIGNIFICANCE AND IMPACT OF THE STUDY: The study suggested less dependability of metabolic data alone as an identification tool.

Isolation of fluorescent pseudomonads from the rhizosphere of banana plants antagonistic towards root necrosing fungi.

Total aerobic bacteria and fluorescent pseudomonads were counted in bulk and rhizospheric soils of banana plants of 14 plantations in Martinique (French West Indies). Fluorescent Pseudomonas isolates were then identified and investigated for in vitro antagonism towards Cylindrocladium sp., a fungal pathogen of banana roots. Total aerobic bacteria and fluorescent pseudomonads were significantly more abundant in rhizospheric soils than in bulk soils. Among 58 fluorescent Pseudomonas isolates, 41 were identified as Pseudomonas fluorescens biovar V and 17 as Ps. putida biovar A. Six strains exhibited an antagonism towards Cylindrocladium isolates. Among them, Ps. putida strain 93.1 totally blocked fungal growth. No relationship was established between the antifungal effect and enzyme or hydrogen cyanide production by bacteria, suggesting that siderophores and other compounds were involved in fungal inhibition. Antagonistic fluorescent pseudomonads represent a potential for the biological control of banana root infections by Cylindrocladium sp.

Physicochemical, microbiological and sensory changes in stored plantain chips.

Plantain chips were produced from unripe plantain fruits. The chips were packed in polyethylene bags and stored at 30 +/- 2 degrees C for 1, 2 and 3 months, respectively. The storage stability of the chips was evaluated by analyzing periodically for changes in the physicochemical, microbiological and sensory characteristics. Protein and ash contents of the chips did not change (p > 0.05) over time. Fat decreased slightly (p > 0.05) over time. Vitamin C decreased and was negatively correlated with storage time (r = -95; p < 0.05). Peroxide value and microbial count increased with storage (p < 0.05). Sensory scores for chips did not change (p > 0.05) at 2 months storage, but, thereafter, decreased (p < 0.05).

Characterization of Gibberella fujikuroi complex isolates by fumonisin B1 and B2 analysis and by RAPD and restriction analysis of PCR-amplified internal transcribed spacers of ribosomal DNA.

Twenty nine isolates of Fusarium spp. (twenty four of them belonging to the Gibberella fujikuroi complex) isolated from banana and corn from different geographical regions were analyzed for their ability to produce fumonisins B1 and B2 and for genetic relatedness using random amplified polymorphic DNA (RAPD) and restriction analysis of PCR amplification products of the 5.8s ribosomal DNA-intervening internal transcribed spacer regions (ITS I-5.8S-ITS II). For RAPD analysis, six of twenty oligonucleotide primers were selected after testing with five Fusarium spp. isolates and used to characterize 24 additional isolates. DNA fragments from the 29 isolates of Fusarium spp., which were approximately 560 bp, were amplified with the universal primers ITS1 and ITS4. The restriction enzymes HaeIII, MboI, HpaII and MspI were useful for distinguishing the isolates. The RAPD analysis permitted to find interspecific differences among the isolates of Fusarium spp., between isolates with low and high capacity of fumonisin production and among isolates from different hosts. The restriction fragment length polymorphism (RFLP-PCR) analysis permitted to distinguish among different species of Fusarium. In combination with morphological analysis, the results of this research may find an application for the diagnosis of unknown Fusarium spp. and, particularly, for the characterization of fumonisin-producing isolates, which may be very useful in the food technology field.

Characterization of lactic acid bacteria isolated from a Thai low-salt fermented fish product and the role of garlic as substrate for fermentation.

Lactic acid bacteria (LAB) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a Thai low-salt fermented fish product) were characterized by API 50-CH and other phenotypic criteria. Lactococcus lactis subsp. lactis and Leuconostoc citreum were specifically associated with fish fillet and minced fish, Lactobacillus paracasei subsp. paracasei with boiled rice and Weisella confusa with garlic mix and banana leaves. In addition, Lactobacillus plantarum, Lactobacillus pentosus and Pediococcus pentosaceus were isolated from raw materials. A succession of aciduric, homofermentative lactobacillus species, dominated by Lb. plantarum/pentosus, was found during fermentation. In total, 9% of the strains fermented starch and 19% fermented garlic, the two main carbohydrate components in som-fak. The ability to ferment garlic was paralleled by a capacity to ferment inulin. An increased percentage of garlic fermenting strains was found during fermentation of som-fak, from 8% at day 1 to 40% at day 5. No starch fermenting strains were isolated during fermentation. Three mixed LAB cultures, composed of either starch fermenting Lc. lactis subsp. lactis and Lb. paracasei subsp. paracasei, or garlic fermenting Lb. plantarum and Pd. pentosaceus, or a combination of these strains were inoculated into laboratory prepared som-fak with or without garlic. In som-fak without garlic, pH was above 4.8 after three days, irrespective of addition of mixed LAB cultures. The starch fermenting LAB were unable to ferment som-fak and sensory spoilage occurred after three days. Fermentation with the combined mix of starch and garlic fermenting strains led to production of 2.5% acid and a decrease in pH to 4.5 in two days. The fermentation was slightly slower with the garlic fermenting strains alone. This is the first report describing the role of garlic as carbohydrate source for LAB in fermented fish products.

Multiple evolutionary origins of the fungus causing Panama disease of banana: concordant evidence from nuclear and mitochondrial gene genealogies.

Panama disease of banana, caused by the fungus Fusarium oxysporum f. sp. cubense, is a serious constraint both to the commercial production of banana and cultivation for subsistence agriculture. Previous work has indicated that F. oxysporum f. sp. cubense consists of several clonal lineages that may be genetically distant. In this study we tested whether lineages of the Panama disease pathogen have a monophyletic origin by comparing DNA sequences of nuclear and mitochondrial genes. DNA sequences were obtained for translation elongation factor 1alpha and the mitochondrial small subunit ribosomal RNA genes for F. oxysporum strains from banana, pathogenic strains from other hosts and putatively nonpathogenic isolates of F. oxysporum. Cladograms for the two genes were highly concordant and a partition-homogeneity test indicated the two datasets could be combined. The tree inferred from the combined dataset resolved five lineages corresponding to "F. oxysporum f. sp. cubense" with a large dichotomy between two taxa represented by strains most commonly isolated from bananas with Panama disease. The results also demonstrate that the latter two taxa have significantly different chromosome numbers. F. oxysporum isolates collected as nonpathogenic or pathogenic to other hosts that have very similar or identical elongation factor 1alpha and mitochondrial small subunit genotypes as banana pathogens were shown to cause little or no disease on banana. Taken together, these results indicate Panama disease of banana is caused by fungi with independent evolutionary origins.