Background This study aimed to isolate potent thermophilic and amylolytic bacteria from a hot spring of Pharaoh’s bath, Sinai, Egypt, and screen its degradative activity. The amylolytic activity was further optimized using a statistical full factorial design followed by response surface methodology. Results A thermophilic bacterium was isolated from the hot spring of Pharaoh’s Bath, Sinai, Egypt. The isolate produced amylase, cellulase, and caseinase and was identified by 16S rRNA gene sequencing as Parageobacillus thermoglucosidasius Pharon1 (MG965879). A growth medium containing 1% soluble starch was found to optimize the amylase production. Dinitrosalycalic acid method (DNS) was used to estimate the amount of reducing sugar produced. Statistical full factorial and response surface designs were employed to optimize physical variables affecting the α-amylase production and determine the significant interactions of the studied variables during the fermentation process. According to the results obtained by the response optimizer, the maximum amylase activity reached 76.07 U/mL/ min at 54.1°C, pH 5.6 after 98.5 h incubation under aerobic conditions. Moreover, the produced enzyme was thermostable and retained most of its activity when exposed to a high temperature of 100°C for 120 min. Maximum enzyme activity was attained when the enzyme was incubated at 70°C for 30 min. Conclusions This is the first report of the production of thermostable α-amylase by the potent thermophilic Parageobacillus thermoglucosidasius. The enzyme endured extreme conditions of temperature and pH which are important criteria for commercial and industrial applications.

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Egyptian deserts are an underexplored ecological niche, especially the Sinai Peninsula. In our recent study, we explored this extreme environment and shed light on the bioactive capabilities of desert Actinobacteria isolated from Sinai. Fifty desert Actinobacteria were isolated from the Sinai desert using mineral salt media, basal media, and starch casein media. The filtrate of Streptomyces sp. DH 7 displayed a high inhibitory effect against multidrug-resistant Staphylococcus aureus (MRSA) strains. The 16S rDNA sequencing confirmed that isolate DH7 belongs to the genus Streptomyces. The NJ phylogenetic tree showed relatedness to the Streptomyces flavofuscus strain NRRL B-2594 and Streptomyces pratensis strain ch24. The minimum inhibitory concentrations against MRSA were 16 and 32 μg/μL. Chemical investigation of the ethyl acetate extract of Streptomyces sp. DH7 led to the isolation and purification of natural products 1–4. Structure elucidation of the purified compounds was performed using detailed spectroscopic analysis including 1 and 2D NMR, and ESI-MS spectrometry. To the best of our knowledge, this is the first report for the isolation of compounds 1–4 from a natural source, while synthetic analogs were previously reported in the literature. Compounds 3–4 were identified as actinomycin D analogues and this is the first report for the production of actinomycin D analogs from the Sinai desert with an inhibitory effect against MRSA. We indorse further study for this analog that can develop enhanced antimicrobial activities. We confirm that the desert ecosystems in Egypt are rich sources of antibiotic-producing Actinobacteria.

The aim of this study was to investigate and trace the biodegradation products of the pesticide malathion in a comparative manner by two different lactobacilli strains; L. casei (NRRL1922) and L. acidophilus (NRRL 23431). The two strains were cultivated separately into skimmed milk supplemented with 5 ng/ml malathion. After incubation under the appropriate conditions, randomized samples were taken at intervals 24, 48, 72 and 120 hours along with control samples and analyzed for the presence of malathion and its degradation products by the GC-MS spectrometry; As well as, analyzed to record the level of phosphatase enzyme which suggested to be involved in the biodegradation process. The results showed a high ability of the two tested strains to degrade malathion with a superiority of L. acidophilus (NRRL 23431) over L. casei (NRRL 1922). The level of phosphatase enzyme was elevated in both strains in the presence of malathion and decreased gradually upon the depletion of malathion from the sample, which reflects the role of the phosphatase enzyme in the biodegradation process.

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Background American foulbrood (AFB) is one of the potent and highly contagious bacterial diseases affecting honeybees of Apis mellifera and A. cerana species. Paenibacillus larvae larvae (P. l. larvae) is the causative agent of AFB. The present study evaluated a novel technique to control AFB disease, in vitro, depending on double-coated microencapsulated probiotics. Microencapsulation was performed for the preservation of five different locally isolated, honeybee endogenous lactic acid bacteria (LAB) (Lactobacillus plantarum MK780211, L. plantarum MK780215, L. kunkeei MK780216, L. kunkeei MK780218 and Lactobacillus sp. MK780212). Results Extrusion technique was used to encapsulate each strain separately in alginate beads coated with resistant starch (Hi-maize) and chitosan. Encapsulation efficiency was determined by testing the cell viability after encapsulation process, and it was ranging between 93.1 and 95.5%. The antimicrobial activity of both free and encapsulated LABs against P. l. larvae was evaluated by the agar well diffusion method. The encapsulation process decreased the activity of all the tested probiotics to some extent, except Lactobacillus sp. MK780212 which caused complete inhibition for P. l. larvae with good shelf-life expectancy time, for a month, compared to its free cells. The effect of whole capsule and its components was evaluated to ensure the activity of the tested probiotics. Conclusion The laboratory-controlled experiments revealed that the microencapsulation process with double coating can be used with some probiotics efficiently without affecting their activity.