Fermentation of Multi-targeted Products: A Statistical Approach Discussed the Production of Cell Wall Hydrolytic Enzymes From Streptomyces Rochei for Control of Pathogenic Fungi

The production of synergistically multi-acting cell wall hydrolyzing enzymes was observed in the culture filtrate of a strain molecularly characterized as Streptomyces rochei MZ227230. It showed high ability to produce chitinase, glucanase, protease and whole cell-wall lytic enzymes “WCL”. The simultaneous optimization production of several enzymes is a true challenge since each enzyme has its own favorable requirements that may not support or contradict the production of the others. Thus, the current study discussed such issue through application of statistical modeling. Productivity of the enzymes was monitored in different media and superiority of the modified TLE medium (M4) was clearly noticed. Box-Behnken design (BBD) using the key components of M4 (C. albicans cell walls, baker yeast, chitin and peptone) followed by independent analysis for productivity of each enzyme helped to conduct four significant models describing four media that were specifically optimized to produce the utmost yields of chitinase (14.97), glucanase (27.89), protease (137.59) and WCL (65.28 U/ml). Pearson’s correlation analysis indicated the impossibility to potentiate the tested enzymes to the utmost yields at the same time. However, simultaneous solution for all models’ equations identified a coproduction medium that potentiated more than 80% of the maximal yields for all enzymes. Finally, the crude filtrate showed potent fungicidal effects against Fusarium graminearum, Mucor racemosus, Fusarium solani, and Candida albicans which were proven to be attributed to the hydrolytic activity of the filtrate basing on dose and time-dependent release of C. albicans cell constituents DNA, RNA and protein as a model microbe.

Predicting Cell Wall Lytic Enzymes Using Combined Features

Due to the overuse of antibiotics, people are worried that existing antibiotics will become ineffective against pathogens with the rapid rise of antibiotic-resistant strains. The use of cell wall lytic enzymes to destroy bacteria has become a viable alternative to avoid the crisis of antimicrobial resistance. In this paper, an improved method for cell wall lytic enzymes prediction was proposed and the amino acid composition (AAC), the dipeptide composition (DC), the position-specific score matrix auto-covariance (PSSM-AC), and the auto-covariance average chemical shift (acACS) were selected to predict the cell wall lytic enzymes with support vector machine (SVM). In order to overcome the imbalanced data classification problems and remove redundant or irrelevant features, the synthetic minority over-sampling technique (SMOTE) was used to balance the dataset. The F-score was used to select features. The Sn, Sp, MCC, and Acc were 99.35%, 99.02%, 0.98, and 99.19% with jackknife test using the optimized combination feature AAC+DC+acACS+PSSM-AC. The Sn, Sp, MCC, and Acc of cell wall lytic enzymes in our predictive model were higher than those in existing methods. This improved method may be helpful for protein function prediction.

Cell Wall Lytic Enzymes And Their Role In Bacteriophages Infection

Use of chemical pesticides has been shown to have many negative side effects, such as insecticide resistance and resurgence, an outbreak of secondary pests and diseases, the disappearance of parasitoid and predator species as well as residual effects on food crops and on the environment. Over the past 60 years, both the number of agricultural toxins in the environment and incidence rates of toxin-related diseases has increased dramatically. The most effective way to combat this problem is through the use of natural predators. One of the best examples of this is the use of host-specific bacteriophages to control bacterial diseases. The mechanism of infection is a very interesting one. To break through the bacterial cell wall the bacteriophages must produce a range of lytic enzymes. This review will examine and discuss studies of these site-specific cell wall lytic enzymes and their roles in the infection of bacteriophages.

Roles of LysM and LytM domains in resuscitation-promoting factor (Rpf) activity and Rpf-mediated peptidoglycan cleavage and dormant spore reactivation

Bacterial dormancy can take many forms, including formation of Bacillus endospores, Streptomyces exospores, and metabolically latent Mycobacterium cells. In the actinobacteria, including the streptomycetes and mycobacteria, the rapid resuscitation from a dormant state requires the activities of a family of cell-wall lytic enzymes called resuscitation-promoting factors (Rpfs). Whether Rpf activity promotes resuscitation by generating peptidoglycan fragments (muropeptides) that function as signaling molecules for spore germination or by simply remodeling the dormant cell wall has been the subject of much debate. Here, to address this question, we used mutagenesis and peptidoglycan binding and cleavage assays to first gain broader insight into the biochemical function of diverse Rpf enzymes. We show that their LysM and LytM domains enhance Rpf enzyme activity; their LytM domain and, in some cases their LysM domain, also promoted peptidoglycan binding. We further demonstrate that the Rpfs function as endo-acting lytic transglycosylases, cleaving within the peptidoglycan backbone. We also found that unlike in other systems, Rpf activity in the streptomycetes is not correlated with peptidoglycan-responsive Ser/Thr kinases for cell signaling, and the germination of rpf mutant strains could not be stimulated by the addition of known germinants. Collectively, these results suggest that in Streptomyces, Rpfs have a structural rather than signaling function during spore germination, and that in the actinobacteria, any signaling function associated with spore resuscitation requires the activity of additional yet to be identified enzymes.

Green Production and Biotechnological Applications of Cell Wall Lytic Enzymes

: Energy demand is constantly growing, and, nowadays, fossil fuels still play a dominant role in global energy production, despite their negative effects on air pollution and the emission of greenhouse gases, which are the main contributors to global warming. An alternative clean source of energy is represented by the lignocellulose fraction of plant cell walls, the most abundant carbon source on Earth. To obtain biofuels, lignocellulose must be efficiently converted into fermentable sugars. In this regard, the exploitation of cell wall lytic enzymes (CWLEs) produced by lignocellulolytic fungi and bacteria may be considered as an eco-friendly alternative. These organisms evolved to produce a variety of highly specific CWLEs, even if in low amounts. For an industrial use, both the identification of novel CWLEs and the optimization of sustainable CWLE-expressing biofactories are crucial. In this review, we focus on recently reported advances in the heterologous expression of CWLEs from microbial and plant expression systems as well as some of their industrial applications, including the production of biofuels from agricultural feedstock and of value-added compounds from waste materials. Moreover, since heterologous expression of CWLEs may be toxic to plant hosts, genetic strategies aimed in converting such a deleterious effect into a beneficial trait are discussed.