Effect of Chinese medicinal herbal residues compost on tomato and Chinese cabbage plants: Assessment on phytopathogenic effect and nutrients uptake.

Chinese medicinal herbal residues (CMHRs) are known for their antipathogenic properties due to the presence of bioactive compounds. Hence, CMHRs could be used as a potential resource to produce biofertilizer with antipathogenic properties for agricultural applications. In this study, a novel approach was used by utilizing the waste-derived biofertilizer, i.e., CMHRs compost (CMHRC) as a nutrient supplier as well as an organic bioagent against Alternaria solani (A. solani) and Fusarium oxysporum (F. oxysporum) on tomato (Lycopersicon esculentum) and Chinese cabbage (Brassica rapa subsp. Chinensis) plants. The experiments were conducted under greenhouse conditions using locally collected acidic soil wherein 2%, 5% and 10% CMHRC (dry weight) along with 5% food waste compost were used as treatments. In addition, only soil and soil with phytopathogens were used as control treatments. The results suggested that amending the compost into acidic soil significantly increased the pH to a neutral level along with enhanced uptake of nutrients. Among all the treatments, 5% CMHRs compost addition increased the tomato plant biomass production to 4.9 g/pot (dry weight) compared to 2.2 g/pot in control. A similar trend was observed in Chinese cabbage plants and the improved plant biomass production could be attributed to the combined effect of strong nutrient absorption ability by healthy roots and enhanced nutrient supply. At 5% CMHRC application rate, the nitrogen uptake by tomato and Chinese cabbage plants increased by 78% and 62%, respectively, whereas phosphorous uptake increased by 75% and 25%, respectively. The reduction in A. solani by 48% and F. oxysporum by 54% in the post-harvested soil of 5% CMHRC treatment against the control demonstrated the anti-phytopathogenic efficiency of CMHRC compost. Hence, the present study illustrates the beneficiary aspects of utilizing CMHRs to produce biofertilizer with anti-phytopathogenic properties which can be safely used for tomato and Chinese cabbage plant growth.

Application of recombinant Pediococcus acidilactici BD16 (fcs +/ech +) for bioconversion of agrowaste to vanillin.

Biotechnological production of vanillin is gaining momentum as the natural synthesis of vanillin that is very expensive. Ferulic acid (FA), a costly compound, is used as the substrate to produce vanillin biotechnologically and the making process is still expensive. Therefore, this study investigated the practical use of an agrobiomass waste, rice bran, and provides the first evidence of a cost-effective production of vanillin within 24 h of incubation using recombinant Pediococcus acidilactici BD16 (fcs +/ech +). Introduction of two genes encoding feruloyl CoA synthetase and enoyl CoA hydratase into the native strain increased vanillin yield to 4.01 g L-1. Bioconversion was monitored through the transformation of phenolic compounds. A hypothetical metabolic pathway of rice bran during the vanillin bioconversion was proposed with the inserted pathway from ferulic acid to vanillin and compared with that of other metabolic engineered strains. These results could be a gateway of using recombinant lactic acid bacteria for industrial production of vanillin from agricultural waste.

Improved dewatering of CEPT sludge by biogenic flocculant from Acidithiobacillus ferrooxidans.

Bioleaching using an iron-oxidizing bacterium, Acidithiobacillus ferrooxidans, and its biogenic flocculants was evaluated to improve the dewaterability of chemically enhanced primary treatment (CEPT) sewage sludge. CEPT sludge in flasks was inoculated with A. ferrooxidans culture, medium-free cells and the cell-free culture filtrate with and without the energy substance Fe(2+), and periodically the sludge samples were analysed for the dewaterability. This investigation proves that bioleaching effectively improved the sludge dewaterability as evidenced from drastic reduction in capillary suction time (≤20 seconds) and specific resistance to filtration (≥90%); however, it requires an adaptability period of 1-2 days. On the other hand, the biogenic flocculant produced by A. ferrooxidans greatly decreased the time-to-filtration and facilitated the dewaterability within 4 h. Results indicate that rapid dewatering of CEPT sludge by biogenic flocculants provides an opportunity to replace the synthetic organic polymer for dewatering.

Preliminary occurrence studies of antibiotic residues in Hong Kong and Pearl River Delta.

An improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to investigate the occurrence of selected antibiotic residues in Hong Kong and Pearl River Delta. LC and MS parameters were optimized to produce the maximum analytical responses for each compound. The established method targeted five groups of antibiotics, namely, macrolides, sulfonamides, tetracyclines, quinolones, and amphenicols. The method was validated for three types of environmental water matrices, namely, reservoir, river, and estuarine waters. Low detection limits of 0.17-0.18 ng/L for macrolides, 0.22-0.34 ng/L for quinolones, 0.67-1.65 ng/L for tetracyclines, and 0.27-0.56 ng/L for sulfonamides were obtained. No apparent interferences were observed in the chromatograms of all antibiotics groups. The developed method was preliminarily used to analyze water samples collected from Yuen Long River in New Territories, Hong Kong and four sites along the Pearl River Delta. Results showed that high level of tetracycline was found among the groups tested in the local river samples. In Pearl River Delta, we identified significant levels of erythromycin, roxithromycin, and sulfadiazine in Shenzhen Reservoir.

Degradation of tetracycline and sulfadiazine during continuous thermophilic composting of pig manure and sawdust.

During composting, the thermophilic phase resulted in high degradation of antibiotics in the composting mass; thus temperature is considered as the major factor for degradation of antibiotics. Therefore, to achieve complete removal of antibiotics, the effect of continuous thermophilic composting on the degradation of antibiotics and their effect on antibiotic resistant bacteria in the pig manure were evaluated. Pig manure was mixed with sawdust, spiked with tetracycline (10 and 100 mg/kg) and sulfadiazine (2 and 20mg/kg) on dry weight (DW) basis and composted at 55 degrees C for six weeks. Based on the organic decomposition, the antibiotics did not affect the composting process significantly, but negatively influenced the bacterial population. Tetracycline clearly exhibited a negative but marginal influence on carbon decomposition at 100 mg/kg level. The bacterial population initially decreased steeply approximately 2 logs and slowly increased thereafter. Sulfadiazine and tetracycline resistant bacterial populations were stable/marginally increased after an initial decrease of about 2 or 3-5 logs, respectively. Sulfadiazine was not detectable after three days; whereas, approximately 8% of tetracycline was detected after 42 days of composting with a t(1/2) of approximately 11 days, irrespective of the initial concentration. The presence of tetracycline in the compost after 42 days of thermophilic composting indicates the involvement of a mesophilic microbial-mediated degradation; however, further studies are required to confirm the direct microbial involvement in the degradation of antibiotics.

Enhanced solubilization and desorption of organochlorine pesticides (OCPs) from soil by oil-swollen micelles formed with a nonionic surfactant.

The effect of oil-swollen micelles formed with nonionic surfactant polyoxyethylene sorbitan monooleate (Tween 80), cosurfactant 1-pentanol, and linseed oil on the solubilization and desorption of organochlorine pesticides (OCPs) including DDT and γ-HCH from both loam soil and clay soil were investigated. Results showed that the solubilizing capacities of oil-swollen micelles were dependent on the critical micelle concentration (CMC) of Tween 80. Once the concentrations of oil-swollen micelles exceeded the CMC of Tween 80, the oil-swollen micelles exhibited much higher solubilizing capacity than empty Tween 80 micelles for the two OCPs. Desorption tests revealed that oil-swollen micelles could successfully enhance desorption of OCPs from both loam soil and clay soil. However, compared with the efficiencies achieved by empty Tween 80 micelles, oil-swollen micelles exhibited their superiority to desorb OCPs only in loam soil-water system while was less effective in clay soil-water system. Distribution of Tween 80, 1-pentanol and linseed oil in soil-water system revealed that the difference in the sorption behavior of linseed oil onto the two soils is responsible for the different effects of oil-swollen micelles on the desorption of OCPs in loam soil and clay soil systems. Therefore, oil-swollen micelles formed with nonionic surfactant Tween 80 are better candidates over empty micelle counterparts to desorb OCPs from soil with relatively lower sorption capacity for oil fraction, which may consequently enhance the availability of OCPs in soil environment during remediation processes of contaminated soil.

In-vessel co-composting of horse stable bedding waste and blood meal at different C/N ratios: process evaluation.

Abattoir blood meal is rich in nitrogen and its potential as a co-composting material for horse stable bedding waste was evaluated at two C/N ratios -32 (LBM, low blood meal) and 16 (HBM, high blood meal) - to improve the nutrient contents of the final compost. The mix was composted for 7 days in a 10 tonne/day in-vessel composter and cured aerobically. After 56 days ofcomposting, the ammoniacal-N, CO2 evolution rate and C/N ratio of both LBM and HBM were within the guideline values; however, delayed decomposition and lower seed germination index were observed with HBM. In addition, HBM resulted in 84% loss of the initial ammoniacal-N. Almost similar organic decompositions, 62.4% and 59.6% with LBM and HBM, respectively, were achieved. However, a stable compost product can be obtained within 6-7 weeks with LBM, whereas >8 weeks were required for HBM composting. Therefore, co-composting at the C/N ratio of 32 is recommended to achieve odour-free and faster composting.

Two-phase anaerobic digestion of food waste: Effect of semi-continuous feeding on acidogenesis and methane production.

In present investigation, effect of diverting acidogenic off-gas from leached bed reactor (LBR) to up-flow anaerobic sludge blanket (UASB) reactor during semi-continuous food waste (FW) anaerobic digestion was evaluated. In test LBR headspace pressure (3.3 psi) was maintained with intermittent headspace gas transfer into UASB. In control, same headspace pressure was maintained without gas transfer. The semi-continuous FW addition affected the characteristics and production of leachate in control and test LBR. The cumulative COD, total soluble products and methane yields were 1.26, 1.37 and 3 times higher in the test LBR than the control. The acetate and methane yields from test LBR were 697.8 g·kgVSadded-1 and 167.55 mL·gCOD-1feeding. Acidogenic gas transfer maintained low partial pressure of hydrogen and the hydrogen to carbon-di-oxide ratio in the headspace of LBR, which were thermodynamically favorable for microbial metabolism and concomitant high-rate production of acetate-rich volatile fatty acid and methane-rich biogas from FW.

Co-composting of food waste and swine manure augmenting biochar and salts: Nutrient dynamics, gaseous emissions and microbial activity.

The prominent characteristics of the biochar, high porosity, sorption capacity with low density improve the aeration, making it a desirable amendment material for composting process. The composting efficiency was analysed by the impact of rice husk biochar amendment (0, 2, 4, 6, 8 and 10%) in the presence of salts for the co-composting of food waste and swine manure, in composting reactors for 50 days. Results revealed that biochar amendment had improved the degradation rates by microbial activities in comparison with control. The final compost quality was improved by reducing the bulk density (29-53%), C/N ratio (29-57%), gaseous emissions (CO2, CH4, and NH3) and microbial pathogens (Escherichia coli and Salmonella sp.). However, 6% biochar amendment had significant improvement in compost quality, degradation rates and nutritional value which is recommended as the ideal ratio for obtaining mature compost from the feedstock, food waste and swine manure.

Microemulsion-enhanced remediation of soils contaminated with organochlorine pesticides.

Soil contaminated by organic pollutants, especially chlorinated aromatic compounds such as DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane), is an environmental concern because of the strong sorption of organochlorine pesticide onto the soil matrix and persistence in the environment. The remediation of organochlorine pesticide contaminated soils through microemulsion is an innovative technology to expedite this process. The remediation efficiency was evaluated by batch experiments through studying the desorption of DDT and hexachlorocyclohexane (y-HCH) and sorption of microemulsion composed of Triton X-100, 1-pentanol and linseed oil in the soil-surfactant-water suspension system. The reduction of desorption efficiency caused by the sorption loss of microemulsion components onto the soil could be corrected by the appropriate adjustment of C/S (Cosurfactant/Surfactant) and O/S (Oil/Surfactant) ratio. The C/S and O/S ratios of 1:2 and 3:20 were suitable to desorb DDT and gamma-HCH from the studied soils because of the lower sorption of Triton X-100 onto the soil. Inorganic salts added in microemulsion increased the pesticides desorption efficiency of pesticides and calcium chloride has a stronger ability to enhance the desorption of DDT than sodium chloride. From the remediation perspective, the balance of surfactant or cosurfactant sorbed to soil and desorption efficiency should be taken into consideration to enhance the remediation of soils contaminated by organochlorine pesticides.

Influence of different mixing ratios on in-vessel co-composting of sewage sludge with horse stable straw bedding waste: maturity and process evaluation.

Composting sewage sludge alone would reduce the decomposition efficiency due to free limited porosity in sludge. To alleviate this, the use of horse stable straw bedding waste (HSB) was evaluated as a co-composting material with sewage sludge in a 10 tonnes day(-1) in-vessel composter for a period of 7 days before curing in a static aeration pile. Sludge was mixed with HSB at 1 : 1.5 (HSL) and 1 : 2.9 (LSL) on a fresh weight basis. After a composting period of 56 days, both mixing ratios demonstrated to be feasible with LSL having a better organic decomposition and a shorter time to reach maturity. The overall decomposition rates were 52.0 and 58.9% (dry weight basis) for HSL and LSL, respectively. In both treatments, temperature in the in-vessel composters could reach 65°C, which was sufficient to remove the pathogens. Although both products were free of pathogens, HSL exhibited a higher ammoniacal nitrogen contents but a lower seed germination index than that of LSL indicating a higher phytotoxicity and a longer curing period would be required. It can be concluded that HSB provided a better composting conditions at a mixing ratio of 1 : 2.9.

Microbial communities and bacterial diversity of spruce, hemlock and grassland soils of Tatachia Forest, Taiwan.

To evaluate the bacterial diversity of Tatachia Forest soils, 16S rDNA clone libraries of the spruce, hemlock and grassland soils were constructed. Further, the influence of physicochemical and biological properties of soil on microbial ecology, pH, moisture content, microbial population and biomass were also analyzed. The soil pH increased with the increasing of soil depth; whereas the microbial population, biomass, moisture content, total organic carbon and total nitrogen were reverse. Microbial populations were the highest in the summer season which also correlated with the highest moisture content. The phylogenetic analyses revealed that the clones from nine 16S rDNA clone libraries represented Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Gemmatimonadetes, Planctomycetes, Verrucomicrobia, candidate division TG1 and candidate division TM7. Members of Proteobacteria, Acidobacteria and Actinobacteria constituted 42.2, 35.1 and 7.8 % of the clone libraries, respectively; whereas the remaining bacterial divisions each comprised <3 %. The spruce site had the highest bacterial diversity among the tested sites, followed by the hemlock sites and the grassland sites with the least. The bacterial community is the more diverse in the organic layer than that in deeper horizons. Further, bacterial diversity through the gradient horizons was different, indicating that the bacterial diversity in the deeper horizons is not simply the diluted analogs of the surface soils and some microbes dominate only in the deeper horizons.

Bio-hydrogen and methane production from two-phase anaerobic digestion of food waste under the scheme of acidogenic off-gas reuse.

Anaerobic hydrolysis of food wastes sourced from bakery (T1), Chinese restaurant (T2), western-style restaurant (T3), and wet market (T4) were performed in leach bed reactors under the scheme of acidogenic off-gas reuse in methanogenic reactor. Results showed that food waste in T3 achieved the highest hydrogen production of 61.0 L/kg·VSadded. Highest activity of hydrogenase in both leachate and digestate samples confirmed the superior performance of H2 production in T3. Mixed acid fermentation with domination of acetate and butyrate was observed in all four treatments, whereas variations in quantification and speciation of the acidogenic products were closely related to the composition of substrates. High volatile solids (VS) removal (76.7%) was observed in T3 while VS reduction rates of the other treatments ranged from 37 to 55%. High COD production of 0.65 gCOD /g·VSadded together with the reuse of elevated acidogenic off-gas ensured the highest specific CH4 production of 0.42 L/g·VSadded in T3.

Growth and elemental accumulation of plants grown in acidic soil amended with coal fly ash-sewage sludge co-compost.

A greenhouse experiment was conducted to evaluate the growth and heavy-metal accumulation of Brassica chinensis and Agropyron elongatum in 10 and 25% ash-sludge co-compost (ASC)--amended loamy acidic soil (pH 4.51) at two different application rates: 20% and 40% (v/v). Soil pH increased, whereas electrical conductivity decreased with the amendment of ASC to soil. Bioavailable Cu, Zn, and Mn contents of ASC-amended soil decreased, whereas Ni, Pb, and B contents increased. Concentrations of bioavailable Cu, Zn, and Mn in sludge compost (SC)-amended soils were 5.57, 20.8, and 8.19 mg kg(-1), respectively. These concentrations were significantly lower than those in soil receiving an application rate of 20 or 25% ASC as 2.64, 8.48, and 5.26 mg kg(-1), respectively. Heavy metals and B contents of the composting mass significantly increased with an increase in ASC application rate from 20 to 40% (6.2 to 16.6 mg kg(-1) for 10% ASC- and 9.4 to 18.6 mg kg(-1) for 25% ASC-amended soil. However, when the ash content in co-compost increased from 10 to 25% during composting, bioavailable heavy-metal contents decreased. However, B contents increased with an increase in ash content. Addition of co-composts increased the dry-weight yield of the plants, and this increase was more obvious as the ash amendment rate in the co-composts and the ASC application rate increased. In case of B. chinensis, the biomass of 2.84 g/plant for 40% application of 25% ASC was significantly higher than SC (0.352 g/plant), which was 40% application of 10% ASC (0.434 g/plant) treatments. However, in A. elongatum, the differences between biomass of plants grown with 10% (1.34-1.94 g/ plant) and 25% ASC (2.12-2.21 g/plant) were not significantly different. Furthermore, there were fewer plant-available heavy metals in 25% ASC, which decreased the uptake of heavy metals by plants. ASC was favorable in increasing the growth of B. chinensis and A. elongatum. The optimal ash amendment to the sludge composting and ASC application rates were at 25 and 20%, respectively.

Multiplex PCR detection of enterotoxin genes in Aeromonas spp. from suspect food samples in northern Taiwan.

Aeromonads possess an array of virulence factors and are causative agents of a number of human infections. Among them, genes of one cytotoxic (Act) and two cytotonic (Alt, Ast) enterotoxins are implicated in a human diarrheal disease. A rapid, specific, simultaneous detection of these enterotoxin genes in suspected food poisoning samples is not yet reported. Hence, a multiplex PCR assay was designed to amplify the cytotoxic (act), heat-labile cytotonic (alt), and heat-stable cytotonic (ast) enterotoxin genes of aeromonads. The PCR assay was tested with 133 Aeromonas spp. isolated from suspect food poisoning samples and retail samples of poultry and fish from wet markets in and around Taipei, Northern Taiwan. The Aeromonas spp. isolates were divided into six genotypes based on absence or presence of one or more enterotoxin genes. Of these 133 isolates, Aeromonas caviae (52.5%) and Aeromonas hydrophila (43.4%) were the most frequently isolated species from food poisoning samples and retail samples, respectively. Among the species, A. hydrophila had a significantly higher proportion for harboring three enterotoxin genes than had the others, whereas Aeromonas encheleia, considered a nonpathogen, was found harboring three enterotoxin genes. The multiplex PCR assays are rapid and specific, and provide a useful tool for the detection and genotyping of enterotoxin genes of aeromonads.

Chinese medicinal herbal residues as a bulking agent for food waste composting.

This study aimed to co-compost Chinese medicinal herbal residues (CMHRs) as the bulking agent with food waste (FW) to develop a high value antipathogenic compost. The FW, sawdust (SD) and CMHRs were mixed at three different mixing ratios, 5:5:1, 2:2:1 and 1:1:1 on dry weight basis. Lime at 2.25% was added to the composting mix to buffer the pH during the composting. A control without lime addition was also included. The mixtures were composted in 20-L in-vessel composters for 56 days. A maximum of 67.2% organic decomposition was achieved with 1:1:1 mixing ratio within 8 weeks. The seed germination index was 157.2% in 1:1:1 mixing ratio, while other ratios showed <130.0% and the treatment without lime showed 40.3%. Therefore use of CMHRs as the bulking agent to compost food waste at the dry weight ratio of 1:1:1 (FW: SD: CMHRs) was recommended for FW-CMHRs composting.

Influence of lime and struvite on microbial community succession and odour emission during food waste composting.

Lime addition as well as formation of struvite through the addition of magnesium and phosphorus salts provide good pH buffering and may reduce odour emission. This study investigated the odour emission during food waste composting under the influence of lime addition, and struvite formation. Composting was performed in 20-L reactors for 56days using artificial food waste mixed with sawdust at 1.2:1 (w/w dry basis). VFA was one of the most important odours during food waste composting. However, during thermophilic phase, ammonia is responsible for max odour index in the exhaust gas. Trapping ammonia through struvite formation significantly reduced the maximum odour unit of ammonia from 3.0×104 to 1.8×104. The generation and accumulation of acetic acid and butyric acid led to the acidic conditions. The addition of phosphate salts in treatment with struvite formation improved the variation of total bacteria, which in turn increased the organic decomposition.

Lipid accumulation potential of oleaginous yeasts: A comparative evaluation using food waste leachate as a substrate.

In present study, the efficiency of three oleaginous yeasts i.e., Yarrowia lipolytica, Rhodotorula glutinis and Cryptococcus curvatus were compared for their lipid assimilation capacities using three different FW-leachates as a medium. The FW-leachates were collected from dry anaerobic digesters and diluted to achieve carbohydrate content of 25gL-1 prior to yeast inoculations. Around 5% of yeast cultures were individually mixed in three different FW-leachate mediums and incubated under 30°C and 150rpm agitation for 6days. The Y. lipolytica produced high biomass with lipid contents of 49.0±2% on dry weight basis. Whereas, the acetic acid concentration of >6gL-1 inhibited the growth of R. glutinis. The study observed that the selection of appropriate FW-leachate composition is highly important for biolipid accumulation by oleaginous yeasts.

Bio-degradation of oily food waste employing thermophilic bacterial strains.

The objective of this work was to isolate a novel thermophilic bacterial strain and develop a bacterial consortium (BC) for efficient degradation oily food waste. Four treatments were designed: 1:1 mixture of pre-consumption food wastes (PrCFWs) and post-consumption food wastes (PCFWs) (T-1), 1:2 mixture of PrCFWs and PCFWs mixture (T-2), PrCFWs (T-3) and PCFWs (T-4). Equal quantity of BC was inoculated into each treatment to compare the oil degradation efficiency. Results showed that after 15days of incubation, a maximum oil reduction of 65.12±0.08% was observed in treatment T-4, followed by T-2 (55.44±0.12%), T-3 (54.79±0.04%) and T-1 (52.52±0.02%), while oil reduction was negligible in control. Results indicate that the development of oil utilizing thermophilic BC was more cost-effective in solving the degradation of oily food wastes and conversion into a stable end product.