Aims of the Study: The aim of this study was to determine the amount of lignin degradation and biodegradation of organic matter and change of biomass under compost and vermicomposting of sewage sludge.Materials & Methods: Sawdust was added to sewage sludge at 1: 3 weight bases to Carbon to Nitrogen ratio of 25: 1 for composting or vermicomposting. Lignin and volatile solids were determined at different periods, of 0, 10, 30, 40 and 60 days of composting or vermicomposting period to determine the biodegradation of lignocellulose to lignin. Results were expressed as mean of two replicates and the comparisons among means were made using the least significant difference test calculated (p<0.05).Results: After 60 days of experiment period, the initial lignin increased from 3.46% to 4.48% for compost and 3.46% to 5.27% for vermicompost. Biodegradation of lignocellulose was very slow in compost and vermicompost processes. Vermicomposting is a much faster process than compost to convert lignocellulose to lignin (p<0.05). Conclusions: The organic matter losses in sewage sludge composting and vermicomposting are due to the degradation of the lignin fractions. By increasing compost age, the amount of volatile solids will decrease.

In this paper, a novel enzymatic method was evaluated for isolation and purification of wood lignin. The chemical structure of enzymatic lignin (Cellulytic lignin) was compared with conventional Bjorkman method (Milled wood lignin). The chemical structure elucidation was performed with FTIR, quantative 13CNMR, basic elemental analysis and Gel Permeation Chromatography (GPC). The results showed that enzymatic lignin preparation has a better chemical structure than MWL. Comparing to conventional isolation methods, application of an enzyme sequence with reduced milling time could lead to a mild extraction with less structural degradation of lignin. Resulting lignin could be more representative for wood lignin than milled wood lignin.

In this study, optical behavior of methylated and unmethylated Bjorkman lignin from poplar wood and two lignin model compound (phenolic and non phenolic) with b-O-4 linkages was investigated. First, these lignins were precipitated on a cellulosic matrix (Whatman Paper) using different times (0, 5, 10, 15, 20 h) and then matrixcovered surface was analyzed using Attenuated Total Reflectance FTIR technique. The results showed that irradiation altered the chemical structure of all samples. Lignin was the most sensitive component to photodegradation and the intensities of its characteristic bands decreased significantly during the process of irradiation. This was accompanied by formation of new carbonyl groups appearing at 1735 cm-1. Compared with the unmethylated forms, the rate of lignin degradation and carbonyl formation was relatively lower in methylated forms. In other words, methylation of phenolic hydroxyl group reduced the chemical changes induced by irradiation.

In this study, earthworms were collected from the wetlands of northern parts of Sistan and Balouchestan Province at 17 stations. The following nine species were identified: Aporrectodea caliginosa (Savigny, 1826), Ap. jassyensis (Michaelsen, 1891), Ap. longa (Ude, 1885), Ap. rosea (Savigny, 1826), Ap. trapezoides (Dugè s, 1828), Bimastos parvus (Eisen, 1874), Eisenia andrei/fetida complex, E. omranii Latif, Malek and Csuzdi, 2017, and Eiseniella tetraedra (Savigny, 1826). All of the recorded species are new to the east of Iran. The most frequent species were Ap. rosea and Ap. caliginosa; and the rarest one was E. andrei/fetida. Length and total earthworm segments of each species were compared between specimens of the studied area and previous known values from Elburz (north of Iran) and/or Zagros (west of Iran) regions.

Nowadays, finding a catalyst with high quality and ecofriendly thermoset resins is very valuable. This study aimed to investigate the effect of maleated lignin-based polyacid (MAPL) as a catalyst in urea-lignin-glyoxal (ULG) resin. For this reason, a phenolate reaction was done to increase the hydroxyl groups of lignin. Then the modified lignin was reacted with maleic anhydride to obtain polyacid based on maleated lignin. In the next step, different content of MA-PL catalyst (0, 1, 2, and 3 wt%) was added to ULG resin and prepared resins were used in particleboard panels production. Different properties of synthesized resins and panels were measured according to standard methods and were compared with those using ammonium chloride as the control sample. In addition, the thermal behavior of resin before and after adding catalyst was analyzed with Differential Scanning Calorimetry (DSC). Generally, the results of this research indicated that polyacids based lignin could be used as a suitable catalyst for ULG resin. Physical and mechanical test analysis indicated that the addition of catalyst from zero to 3 wt% continuously decrease pH and gelation time. DSC analysis showed that adding extra MA-PL reduces the curing temperature of resin compared with ammonium chloride. Based on the obtained results from manufactured panels, mechanical strength (MOE, MOR, and IB strength) and dimensional stability of the panels was improved by adding 3 wt %MA-PL.

Because of the similarities in appearance between species of Oligochaeta, identify, characterize and differentiate them from each other to determine the population dynamics or molecular and phylogenies studies seems necessary.The aim of this study is to provide an identification key and diagnostic methods for the two species of genus Limnodrilus in the Anzali Wetland. In compare key features to identify and separate the two species was found in L. hoffmeisteri genital sheath is shorter and thicker than Limnodrilus claparedianus. Statistical analysis showed that this is a significant difference between the two species (P<0.05). The average length of the penial sheath in L. hoffmeister and L. claparedianus respectively were 695.31±91.63 and 1117.06±198.31 micrometer. The average length of the upper tooth and lower in L. claparedianus respectively were 9.74 ±1.82 and 6.68±0.91 micrometer, in L. hoffmeister were respectively 7.5±2.07 and 5.64±1.29 micrometer. Although in the visual observations the upper teeth of chaeta of L. claparedianus was longer than L. hoffmeisteri but a significant difference was not observed between the averages of the two species.

In this study, changes in optical behavior of poplar kraft lignin before and after methylation by dimethyl sulphate was determined by measuring optical indices (brightness, K, S, K/S and post-color numbers) of impregnated papers following accelerated photo aging. The structural changes in lignin caused by methylation reaction were verified using FT-IR spectroscopy. The results showed that, by methylation of lignin in methylated lignin-containing papers, the extent and stability of brightness is higher and PC number is lower compared to control samples. In methylated samples, the phenomenon of photo bleaching was observed. Therefore, it can be expressed that, methylation of lignin can prevent the formation of quinone groups and increases the stability of the optical indices in the photo aging conditions.