Influence of microbial inoculants on co-composting of lignocellulosic crop residues with farm animal manure: A review.

The rapidly developing agro-industry generates huge amounts of lignocellulosic crop residues and animal manure worldwide. Although co-composting represents a promising and cost-effective method to treat various agricultural wastes simultaneously, poor composting efficiency prolongs total completion time and deteriorates the quality of the final product. However, supplementation of the feedstock with beneficial microorganisms can mitigate these negative effects by facilitating the decomposition of recalcitrant materials, enhancing microbial enzyme activity, and promoting maturation and humus formation during the composting process. Nevertheless, the influence of microbial inoculation may vary greatly depending on certain factors, such as start-up parameters, structure of the feedstock, time of inoculation, and composition of the microbial cultures used. The purpose of this contribution is to review recent developments in co-composting procedures involving different lignocellulosic crop residues and farm animal manure combined with microbial inoculation strategies. To evaluate the effectiveness of microbial additives, the results reported in a large number of peer-reviewed articles were compared in terms of composting process parameters (i.e., temperature, microbial activity, total organic carbon and nitrogen contents, decomposition rate of lignocellulose fractions, etc.) and compost characteristics (humification, C/N ratio, macronutrient content, and germination index). Most studies confirmed that the use of microbial amendments in the co-composting process is an efficient way to facilitate biodegradation and improve the sustainable management of agricultural wastes. Overall, this review paper provides insights into various inoculation techniques, identifies the limitations and current challenges of co-composting, especially with microbial inoculation, and recommends areas for further research in this field.

Effect of bacterial inoculation on co-composting of lavender (Lavandula angustifolia Mill.) waste and cattle manure.

The primary purpose of this study was to investigate the influence of Cellulomonas flavigena and Streptomyces viridosporus, as a bacterial inoculant, on the compostability of post-extraction lavender waste. The major physicochemical, microbiological, and biological properties of the composting materials were monitored for 161 days. The technology developed was shown to improve the compostability of recalcitrant herbal residues. The use of lavender waste beneficially affected the composting process by extending the thermophilic phase, accelerating the degradation of organic matter, and elevating the viable counts of useful microorganisms; however, adverse effects were also observed, including an increased carbon-to-nitrogen ratio (19.05) and a decreased germination index (93.4%). Bacterial inoculation was found to preserve the nitrogen content (2.50%) and improve the efficiency of biodegradation. The Salmonella- and Escherichia coli-free final composting products were mature, stable, and ready for soil application. To the authors' knowledge, no previous research has investigated the compostability of lavender waste. Likewise, this is the first study that has used strains of C. flavigena and S. viridosporus in combination to facilitate a composting process.

Rapid and sensitive determination of phenol in honey by high-performance liquid chromatography with fluorescence detection.

The objective of this research was to develop a novel high-performance liquid chromatographic (HPLC) method involving a simple sample preparation procedure for the rapid, low-cost, and sensitive quantitation of phenol in honey at levels of regulatory and practical importance. After proper dilution of honey with water, the samples were analyzed by a gradient HPLC system, using a reversed-phase column with fluorescence detection at excitation and emission wavelengths of 270 and 300 nm, respectively. The eluents applied were water-acetonitrile-85% orthophosphoric acid (10:10:0.01, v/v/v) and water-85% orthophosphoric acid (20:0.01, v/v). The retention time of phenol was found to be 14.1 min, and the limit of quantitation for phenol in honey was set at 5 microg/kg. Overall recovery was 98%. The proposed method has been successfully applied to real sample analysis.

Study on the simultaneous determination of some essential and toxic trace elements in honey by multi-element graphite furnace atomic absorption spectrometry.

A multi-element graphite furnace atomic absorption spectrometry (GFAAS) method was elaborated and applied for the simultaneous determination of As, Cd, Cr, Cu, and Pb in various kinds of honey samples (acacia, floral, linden, rape, and milkweed) using the transversally heated graphite atomiser (THGA) with end-capped tubes and integrated graphite platforms (IGPs). For comparative GFAAS analysis, direct (without digestion) and indirect (with digestion in a microwave oven) sample preparation procedures were tested. The effects of several chemical modifiers, such as NH(4)H(2)PO(4), NH(4)H(2)PO(4)-Mg(NO(3))(2), and Pd(NO(3))(2)-Mg(NO(3))(2), were studied to obtain optimal pyrolysis and atomization conditions for the set of analytes studied. The most efficient modifier was proved to be the mixture of 5microg Pd (applied as nitrate) plus 3microg Mg(NO(3))(2), allowing the optimal 600 degrees C pyrolysis and 2300 degrees C atomization temperatures. To prevent the sputtering and foaming of the matrix during the drying and pyrolysis steps of the furnace heating program, the sample and modifier solutions (20+5microl, respectively) were dispensed together onto the IGP of the THGA pre-heated at 80 degrees C. The effect of increasing concentration of honey matrix was studied on the integrated absorbance (A(int)) signals of analytes. The A(int) signals of Cr and Pb were not altered up to 10% (m/v) matrix content in the sample solutions. The matrix effect was slightly suppressive on the A(int) signals of As, Cd, and Cu above 2% (m/v) honey concentration. The recovery was found to be ranged between 85 and 115% for Cd, Cr, Cu, and Pb, whereas it was a lower, compromise value of 70-99% for As. The limit of detection (LOD) data were 1, 0.04, 0.09, 0.3, and 0.6microg l(-1) for As, Cd, Cr, Cu, and Pb, respectively, which values correspond to 20, 0.8, 1.8, 5.3, and 12ng g(-1), respectively, in the solid samples. The characteristic masses were found to be 21 pg As, 1.3 pg Cd, 4 pg Cr, 12 pg Cu, and 33 pg Pb. The As, Cd, Cr, Cu, and Pb contents of the studied 42 honey samples varied significantly, i.e. from below the LOD up to 13, 3.3, 109, 445, and 163ng g(-1), respectively.