https://www.cell.com/trends/microbiology/pdf/S0966-842X(08)00038-3.pdf

Bacillus lipopeptides: versatile weapons for plant disease biocontrol.

The endospore-forming rhizobacterium Bacillus subtilis- the model system for Gram-positive organisms, is able to produce more than two dozen antibiotics with an amazing variety of structures. The produced anti-microbial active compounds include predominantly peptides that are either ribosomally synthesized and post-translationally modified (lantibiotics and lantibiotic-like peptides) or non-ribosomally generated, as well as a couple of non-peptidic compounds such as polyketides, an aminosugar, and a phospholipid. Here I summarize the structures of all known B. subtilis antibiotics, their biochemistry and genetic analysis of their biosyntheses. An updated summary of well-studied antibiotic regulation pathways is given. Furthermore, current findings are resumed that show roles for distinct B. subtilis antibiotics beyond the "pure" anti-microbial action: Non-ribosomally produced lipopeptides are involved in biofilm and swarming development, lantibiotics function as pheromones in quorum-sensing, and a "killing factor" effectuates programmed cell death in sister cells. A discussion of how these antibiotics may contribute to the survival of B. subtilis in its natural environment is given.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2958.2005.04587.x

Bacillus subtilis antibiotics: structures, syntheses and specific functions

▪ Abstract The eutrophication of many ecosystems in recent decades has led to an increased interest in the ecology of nitrogen transformation. Chemolitho-autotrophic ammonia-oxidizing bacteria are responsible for the rate-limiting step of nitrification in a wide variety of environments, making them important in the global cycling of nitrogen. These organisms are unique in their ability to use the conversion of ammonia to nitrite as their sole energy source. Because of the importance of this functional group of bacteria, understanding of their ecology and physiology has become a subject of intense research over recent years. The monophyletic nature of these bacteria in terrestrial environments has facilitated molecular biological approaches in studying their ecology, and progress in this field has been rapid. The ammonia-oxidizing bacteria of the β-subclass Proteobacteria have become somewhat of a model system within molecular microbial ecology, and this chapter reviews recent progress in our knowledge of ...

Ammonia-Oxidizing Bacteria: A Model for Molecular Microbial Ecology

Azo dyes are the most important group of synthetic colorants. They are generally considered as xenobiotic compounds that are very recalcitrant against biodegradative processes. Nevertheless, during the last few years it has been demonstrated that several microorganisms are able, under certain environmental conditions, to transform azo dyes to non-colored products or even to completely mineralize them. Thus, various lignolytic fungi were shown to decolorize azo dyes using ligninases, manganese peroxidases or laccases. For some model dyes, the degradative pathways have been investigated and a true mineralization to carbon dioxide has been shown. The bacterial metabolism of azo dyes is initiated in most cases by a reductive cleavage of the azo bond, which results in the formation of (usually colorless) amines. These reductive processes have been described for some aerobic bacteria, which can grow with (rather simple) azo compounds. These specifically adapted microorganisms synthesize true azoreductases, which reductively cleave the azo group in the presence of molecular oxygen. Much more common is the reductive cleavage of azo dyes under anaerobic conditions. These reactions usually occur with rather low specific activities but are extremely unspecific with regard to the organisms involved and the dyes converted. In these unspecific anaerobic processes, low-molecular weight redox mediators (e.g. flavins or quinones) which are enzymatically reduced by the cells (or chemically by bulk reductants in the environment) are very often involved. These reduced mediator compounds reduce the azo group in a purely chemical reaction. The (sulfonated) amines that are formed in the course of these reactions may be degraded aerobically. Therefore, several (laboratory-scale) continuous anaerobic/aerobic processes for the treatment of wastewaters containing azo dyes have recently been described.

Basic and applied aspects in the microbial degradation of azo dyes

Lipopeptides constitute a structurally diverse group of metabolites produced by various bacterial and fungal genera. In the past decades, research on lipopeptides has been fueled by their antimicrobial, antitumour, immunosuppressant and surfactant activities. However, the natural functions of lipopeptides in the lifestyles of the producing microorganisms have received considerably less attention. The substantial structural diversity of lipopeptides suggests that these metabolites have different natural roles, some of which may be unique to the biology of the producing organism. This review gives a detailed overview of the versatile functions of lipopeptides in the biology of Pseudomonas and Bacillus species, and highlights their role in competitive interactions with coexisting organisms, including bacteria, fungi, oomycetes, protozoa, nematodes and plants. Their functions in cell motility, leading to colonization of novel habitats, and in the formation and development of highly structured biofilms are discussed in detail. Finally, this review provides an update on lipopeptide detection and discovery as well as on novel regulatory mechanisms and genes involved in lipopeptide biosynthesis in these two bacterial genera.

Natural functions of lipopeptides from Bacillus and Pseudomonas: more than surfactants and antibiotics

Characteristics of ammonium removal by heterotrophic nitrification-aerobic denitrification by Alcaligenes faecalis No. 4.

Removal kinetics of hydrogen sulfide, methanethiol and dimethyl sulfide by peat biofilters

Piggery wastewater treatment using Alcaligenes faecalis strain no. 4 with heterotrophic nitrification and aerobic denitrification

Degradation characteristics of hydrogen sulfide, methanethiol, dimethyl sulfide and dimethyl disulfide by Thiobacillus thioparus DW44 isolated from peat biofilter

Mitsuyo Hirai

Papers

Characteristics of ammonium removal by heterotrophic nitrification-aerobic denitrification by Alcaligenes faecalis No. 4.

Removal kinetics of hydrogen sulfide, methanethiol and dimethyl sulfide by peat biofilters

Piggery wastewater treatment using Alcaligenes faecalis strain no. 4 with heterotrophic nitrification and aerobic denitrification

Degradation characteristics of hydrogen sulfide, methanethiol, dimethyl sulfide and dimethyl disulfide by Thiobacillus thioparus DW44 isolated from peat biofilter

Characteristics of a newly isolated fungus, Geotrichum candidum Dec 1, which decolorizes various dyes