Production of biogas from solid organic wastes through anaerobic digestion: a review

Anaerobic digestion treatments have often been used for biological stabilization of solid wastes. These treatment processes generate biogas which can be used as a renewable energy sources. Recently, anaerobic digestion of solid wastes has attracted more interest because of current environmental problems, most especially those concerned with global warming. Thus, laboratory-scale research on this area has increased significantly. In this review paper, the summary of the most recent research activities covering production of biogas from solid wastes according to its origin via various anaerobic technologies was presented.     

Aerobic processing of solid organic wastes for the production of a peat alternative: a review

Aerobic biodegradation is a process of importance in the recycling of organic matter which provides a means of obtaining a stable product by biological oxidative transformation. The basic process and operating process systems are briefly reviewed. The product may be taken for use at different stages of maturity from sanitisation through to a high level of humification and mineralisation. A highly stabilised product has potential as a substitute for peat, having peat-like characteristics as well as a nutrient status.     

Potential uses of milk epithelial cells: a review

Secretions collected from the mammary gland of different species contain heterogeneous populations of cells including lymphocytes, neutrophils, macrophages and epithelial cells in different species. Several factors influence the somatic cell count in milk and the distribution of cell types, such as species, infection status, physiological status and management practices. The epithelial cells are shed into milk during the lactation process. Most of them are viable and exhibit the characteristics of fully differentiated alveolar cells. Primary cultures of epithelial cells from colostrum and milk of humans, baboons, cows and goats together with established cell lines from human and goat milk, provide a good model for the study of lactogenesis, immunity transmission, cancer research and infection by viruses. The RNA extracted from milk cells have been shown to be representative of gene expression in the mammary gland and thus provide a source of material for molecular studies of gene expression and environmental interactions.     

Environmental metabolomics: a critical review and future perspectives

Environmental metabolomics is the application of metabolomics to characterise the interactions of organisms with their environment. This approach has many advantages for studying organism–environment interactions and for assessing organism function and health at the molecular level. As such, metabolomics is finding an increasing number of applications in the environmental sciences, ranging from understanding organismal responses to abiotic pressures, to investigating the responses of organisms to other biota. These interactions can be studied from individuals to populations, which can be related to the traditional fields of ecophysiology and ecology, and from instantaneous effects to those over evolutionary time scales, the latter enabling studies of genetic adaptation. This review provides a comprehensive and current overview of environmental metabolomics research. We begin with an overview of metabolomic studies into the effects of abiotic pressures on organisms. In the field of ecophysiology, studies on the metabolic responses to temperature, water, food availability, light and circadian rhythms, atmospheric gases and season are reviewed. A section on ecotoxicogenomics discusses research in aquatic and terrestrial ecotoxicology, assessing organismal responses to anthropogenic pollutants in both the laboratory and field. We then discuss environmental metabolomic studies of diseases and biotic–biotic interactions, in particular herbivory. Finally, we critically evaluate the contribution that metabolomics has made to the environmental sciences, and highlight and discuss recommendations to advance our understanding of the environment, ecology and evolution using a metabolomics approach.     

Recovery and utilization of proteinous wastes of leather making: a review

Hides and skins, by-product of the meat industry is converted into a value added product namely leather by the tanners. Tanning essentially is the process of converting raw hides and skins into imputrescible substance. The tanning process has number of steps and generates significant quantities of by products and wastes. These solid and liquid wastes pose major environmental problem if not managed effectively. Large–scale production systems are adopted for leather processing in clusters and therefore, the industry receives focus of environmentalists and society. Consequently tremendous pressure is exerted by various pollution regulatory bodies. The hides and skins, after trimming, removal of flesh and fat, are treated with chemicals, which cross-link the collagen fibers to form a stable, durable material. The chemicals used may be derived from traditional vegetable products, or inorganic metal salts. During leather processing number of size reduction, leveling and purification operations are carried out which results in generation of untanned and tanned proteinous waste materials. In this paper, various recovery processes and utilization methodologies of proteinous solid wastes, emanating from leather processing operations prior to tanning is reviewed.     

工业固体废弃物的急性生物毒性研究

工业固体废弃物的急性生物毒性研究谢思琴,顾宗濂,周德智（中国科学院南京土壤研究所,南京２１０００８）Ａｃｕｔｅｂｉｏｔｏｘｉｃｉｔｙｏｆｉｎｄｕｓｔｒｉａｌｓｏｌｉｄｗａｓｔｅｓ￥．ＸｉｅＳｉｑｉｎ;ＧｕＺｏｎｇｌｉａｎａｎｄＺｈｏｕＤｅｚｈｉ（Ｉｎ...     

Antitumor photochemotherapy: biochemical bases, therapeutic uses and perspectives]

The photodynamic therapy of tumors (PDT) is a recent and promising technique for the treatment of tumors which can be reached by the light (directly or by endoscopic illumination). Excellent results are now obtained with hematoporphyrin derivatives such as Photofrin II, provided the concerned tumors are small and well delimited. Porphyrins are transported in blood mainly by lipoproteins, and the low density lipoprotein (LDL) receptor-mediated pathway is probably one of the important factors involved in the selective accumulation of porphyrins by tumor tissues, as cancer cells generally express much more LDL receptors than normal cells. In the present paper, after a brief presentation of the biochemical basis of the light-dependent cytotoxicity of porphyrins, we shall examine the role of lipoproteins, especially LDL, in the transport and the cellular uptake of these compounds. We shall also present recent approaches for the improvement of the PDT efficiency.     

New perspectives of gibberellic acid production: a review

The gibberellins (GAs) are an important group of hormones which exert various effects on promoter and regulator of plant growth. Gibberellic acid (GA₃) is a natural plant hormone, with great economical and industrial importance. It affects stem elongation, germination, elimination of dormancy, flowering, sex expression, enzyme induction and leaf and fruit senescence. Despite its diverse applications, the use of GA₃ is limited due to its high production costs. The industrial process currently used for the production of GA₃ is based on submerged fermentation (SmF) techniques. As an alternative for its production, solid state fermentation (SSF) has also been investigated for its ability to increase the yields of GA₃ with the use of agro-industrial wastes as support/substrate, which contributes to the decreased production costs. This review describes GA₃’s physical, chemical and biological properties, its production by fermentation and new advances that are being carried out with special interest on the SSF technique.     

New perspectives of gibberellic acid production: a review

The gibberellins (GAs) are an important group of hormones which exert various effects on promoter and regulator of plant growth. Gibberellic acid (GA(3)) is a natural plant hormone, with great economical and industrial importance. It affects stem elongation, germination, elimination of dormancy, flowering, sex expression, enzyme induction and leaf and fruit senescence. Despite its diverse applications, the use of GA(3) is limited due to its high production costs. The industrial process currently used for the production of GA(3) is based on submerged fermentation (SmF) techniques. As an alternative for its production, solid state fermentation (SSF) has also been investigated for its ability to increase the yields of GA(3) with the use of agro-industrial wastes as support/substrate, which contributes to the decreased production costs. This review describes GA(3)'s physical, chemical and biological properties, its production by fermentation and new advances that are being carried out with special interest on the SSF technique.     

Microbial processing of fruit and vegetable wastes into potential biocommodities: a review

The review focuses on some of the high value-end biocommodities, such as fermented beverages, single-cell proteins, single-cell oils, biocolors, flavors, fragrances, polysaccharides, biopesticides, plant growth regulators, bioethanol, biogas and biohydrogen, developed from the microbial processing of fruit and vegetable wastes. Microbial detoxification of fruit and vegetable processing effluents is briefly described. The advances in genetic engineering of microorganisms for enhanced yield of the above-mentioned biocommodities are elucidated with selected examples. The bottleneck in commercialization, integrated approach for improved production, techno-economical feasibility and real-life uses of some of these biocommodities, as well as research gaps and future directions are discussed.     

Laurel,Laurus nobilis L.: a review of its botany,traditional uses,phytochemistry and pharmacology

Phytochemistry Reviews - Laurus nobilis L. (Lauraceae), commonly known as laurel, is an evergreen and edible tree that possess biological properties positively correlated with human health. It is a...     

Anaerobic digestion of municipal solid wastes: dry thermophilic performance

The purpose of this study was to analyze the performance of two laboratory-scale reactors (5.0L) treating organic fraction of municipal solid waste (OFMSW): source sorted OFMSW (SS_OFMSW) obtained from a university restaurant and mechanically selected municipal fraction (MS_OFMSW) obtained from a Municipal Treatment Plant placed in Cadiz-Spain. Discontinuous reactors operated at thermophilic (55 degrees C) and dry (20% total solid) conditions. Different decomposition patterns were observed: (1) the SS_OFMSW exhibited the classical waste decomposition pattern with a fast start up phase beginning within 0-5 days and 20-30 and a subsequent stabilization phase. The VS removal was 45% with a cumulative biogas of 120L in approx. 60 days; (2) the MS_OFMSW showed a methanogenic pattern throughout the whole experimental period (60 days) and this gave higher levels of organic biodegradation (56%VSr) and biogas production (82L). Both processes were completed and a high level of cumulative methane production was achieved in less than 60 days, proximally 25-30L.     

Non-isothermal thermogravimetric analysis of oil-palm solid wastes

Thermal decomposition of oil-palm solid wastes, including oil-palm shell, fibre and kernel, was studied by thermogravimetric analysis (TGA). Effect of heating rate and sample particle size on the behaviour of thermogram and kinetic parameters were investigated. The one-step global model, two-step consecutive model and two-parallel reactions model were used to simulate the pyrolysis process of the three materials studied. The one-step global model was able to describe the fractional weight loss upon pyrolysis of oil-palm kernel reasonably well but gave a large deviation for oil-palm shell and fibre. The two-step consecutive model could improve the fitting for oil-palm shell and fibre, but it cannot account for the inflection characteristic of the thermogram. Prediction by the two-parallel reactions model gave the best fitting with the experimental data of all oil-palm wastes under all pyrolysis conditions investigated. This proposed model was also tested with other biomass materials and proved to be satisfactory.     

Helicobacter pylori adhesins: review and perspectives

It is highly unlikely that chronic infection with H. pylori could occur in the absence of adhesin–host cell interactions. Also, there is no evidence that any of the serious outcomes of H. pylori infection such as gastric and duodenal ulcers, gastric cancer or mucosa‐associated lymphoid tissue (MALT) lymphoma could occur without prior colonization of the gastric epithelium mediated by H. pylori adhesins. H. pylori is highly adaptable, as evidenced by the fact that it can occupy a single host for decades. An important facet of this adaptability is its ability to physically interact with various types of host cells and also with host mucins and extracellular matrix proteins using a number of different adhesins displaying a variety of unique receptor specificities. Thus it is highly unlikely that any one particular H. pylori adhesin will ever be proven responsible for a particular outcome such as duodenal ulcer, MALT lymphoma, or adenocarcinoma. Also, while the search for additional H. pylori adhesins should and certainly will continue, we suggest that the scope of this effort should be expanded to include investigations into the patterns of expression and interaction between individual outer membrane proteins. Which of the numerous H. pylori outer membrane proteins (OMPs) actually function as adhesins (i.e., have receptor‐binding sites) and which OMPs are simply necessary for optimal display of the adhesive OMPs? There are many other important questions about H. pylori adhesins waiting to be answered. For example, which adhesins are responsible for loose adherence to host cells and which adhesins are responsible for intimate, or membrane‐to‐membrane, adherence, and do these adhesins normally work in concert or in a sequential fashion? Also, is a specific type of adhesin necessary for type IV protein translocation into host cells and, if so, is adhesin expression coregulated with the effector protein export?     

Mathematical modeling in metal metabolism: Overview and perspectives

A review of mathematical modeling in metal metabolism is presented. Both endogenous and exogenous metals are considered. Four classes of methods are considered: Petri nets, multi-agent systems, determinist models based on differential equations and stochastic models. For each, a basic theoretical background is given, then examples of applications are given, detailed and commented. Advantages and disadvantages of each class of model are presented. A special attention is given to determinist differential equation models, since almost all models belong to this class.     

Mycoplasma attachment to solid surfaces: a review

Mycoplasma attachment to glass in a protein-containing environment requires energization of the cells, probably to provide more accessibility of binding sites. The substance mediating attachment is of protein nature. Studies with monoclonal antibodies on M. pneumoniae suggest a concentration of the binding sites at the tip structure.     

Enantioselective activity of usnic acid: a comprehensive review and future perspectives

Phytochemistry Reviews - This review is focused on the comparison of the biological and pharmacological activities of usnic acid enantiomers. Most of the available data refer to (+)-usnic acid,...     

Thermophilic co-digestion of organic fraction of municipal solid wastes with FOG wastes from a sewage treatment plant: reactor performance and microbial community monitoring

Working at thermophilic conditions instead of mesophilic, and also the addition of a co-substrate, are both the ways to intend to improve the anaerobic digestion of the source-collected organic fraction of municipal solid wastes (SC-OFMSW). Addition of sewage treatment plant fat, oil and grease wastes (STP-FOGW), that are nowadays sent to landfill, would represent an opportunity to recover a wasted methane potential and, moreover, improve the whole process. In this study, after a first period feeding only SC-OFMSW, a co-digestion step was performed maintaining thermophilic conditions. During the co-digestion period enhancements in biogas production (52%) and methane yield (36%) were achieved. In addition, monitoring of microbial structure by using PCR-DGGE and cloning techniques showed that bacterial community profiles clustered in two distinct groups, before and after the extended contact with STP-FOGW, being more affected by the STP-FOGW addition than the archaeal one.