Iranian Research Organization for Science and Technology (IROST)Microbiology, Metabolites and Biotechnology2980-88557220241201Combined Effect of Light Intensity, Photoperiod and Phosphorus Levels on Biomass and Chlorophyll Production in Chlorella vulgaris6779146310.22104/mmb.2024.6990.1144ENHesamShafieiDepartment of Fisheries, Faculty of Natural Resources, University of Tehran, GPO Box 4111, Karaj, IranMehrdadFarhangiDepartment of Fisheries, Faculty of Natural Resources, University of Tehran, GPO Box 4111, Karaj, IranPeterThompsonOceans and Atmosphere, CSIRO, GPO Box 1538 Hobart, TAS 7001, AustraliaNasrinMoazamiDepartment of Biotechnology, Iranian Research Organization for Science & Technology (IROST), Tehran, IranJournal Article20240714Efficient management of economic and sustainable production of microalgae necessitates the strategic utilization of influential growth factors. A pivotal aspect involves optimizing the utilization of photonic energy in conjunction with environmental parameters through elevating algal efficiency to its maximum potential. This investigation delves into the effect of Light Emitting Diodes (LEDs) on different microalgal species under diverse conditions, specifically exploring the impact of blue light intensity, photoperiod, and phosphorus on biomass and chlorophylls a and b content in Chlorella vulgaris. To achieve this objective, a Response Surface Methodology (RSM) approach was employed. The study revealed that the combination of 40 µmol photons . m-2. s-1, 12:12 photoperiod (light:dark), and 80 mg/L phosphorus in media yielded a biomass production of 40*106 cells/ml and 27.7 mg/L chlorophyll a, respectively. Furthermore, response surface analysis identified the optimal condition at 36.58 µmol photons . m-2 . s-1, a 12:12 photoperiod, and 80 mg/L phosphorus in media, which led to 36.24*106 cells/ml, 27.83 mg/L chlorophyll a, and 5.43 mg/L chlorophyll b, with a remarkable approval rating of 93 percent. These findings indicate the potential of LEDs technology to augment biomass production and enhance the content of bioactive compounds in microalgae, thereby endowing them with significant economic value across diverse industries.https://mmb.irost.ir/article_1463_3799e4b1845c8fb38be2874608ed8f51.pdfIranian Research Organization for Science and Technology (IROST)Microbiology, Metabolites and Biotechnology2980-88557220241201The antifungal effect of di-acetyl produced by the isolated lactobacilli from traditional dairy products8091148310.22104/mmb.2024.7182.1153ENAzinLatifiDepartment of Microbiology, Faculty of Sciences, Neyshabur Branch, Islamic Azad University, Neyshabur, IranSamanehDolatabadiDepartment of Microbiology, Faculty of Sciences, Neyshabur Branch, Islamic Azad University, Neyshabur, IranMehdiMotaghiDepartment of Microbiology, Faculty of Sciences, Kerman Branch, Islamic Azad University, Kerman, IranBitaBehboodianDepartment of Animal Science, Kashmar Branch, Islamic Azad University, Kashmar, IranJournal Article20241022Filamentous fungi or molds are the major group of spoilage microorganisms responsible for significant economic losses and serious health risks in the food chain. This study was conducted to evaluate the antifungal effect of di-acetyl produced by Lactobacillus species isolated from traditional fermented product against Penicillium sp. Thirty-three samples of traditional yoghurt, dough, and kefir were cultured, then the isolates were identified by molecular methods (specific PCR and 16S rRNA sequence analysis) and biochemical test. The effects of different media were analyzed in biomass and di-acetyl production. Antifungal activity of di-acetyl was assessed against Penicillium sp. Out of 16 isolates from kefir, yoghurt, and dough, 10 lactic acid bacteria (LAB) isolates were identified as L. casei by biochemical test and molecular methods. MR-VP medium has exhibited the best effect on biomass and di-acetyl production by isolates. GC analysis showed that yoghurt- LABs producing of high di-acetyl have a considerable inhibitory effect on Penicillium sp. The antifungal properties of di-acetyl generated by novel L. casei isolates seem to present a promising advantage, indicating the potential of di-acetyl as a bio-preservative in the food and dairy industries. It may recommended to apply the di-acetyl in fermented product-surface papers to prevent mildew cause by Penicillium sp.https://mmb.irost.ir/article_1483_c08ec7b46132fef14efefe0540570369.pdfIranian Research Organization for Science and Technology (IROST)Microbiology, Metabolites and Biotechnology2980-88557220241201Isolation and Screening of Antibacterial-Producing Endophytic Actinomycetes from Hollyhock (Alcea rosea)92101150810.22104/mmb.2025.7294.1157ENSomayehKarimiDepartment of Microbiology, Faculty of Veterinary Sciences, Ilam University, Ilam, IranFazelPourahmadDepartment of Microbiology, Faculty of Veterinary Sciences, Ilam University, Ilam, IranMostafaNematiDepartment of Microbiology, Faculty of Veterinary Sciences, Ilam University, Ilam, IranJournal Article20241226Actinomycete bacteria are widely recognized for their ability to produce a diverse array of bioactive compounds, particularly antibiotics, and contribute significantly to the discovery of naturally derived antimicrobial agents. This study focused on the isolation and characterization of actinomycete strains from hollyhock (<em>Alcea rosea</em>) plant tissues to assess their antibacterial potential against clinically relevant pathogens. The target pathogens included <em>Bacillus cereus</em>, <em>Staphylococcus aureus</em>, <em>Pseudomonas aeruginosa</em>, and <em>Escherichia coli</em>. A total of 110 bacterial isolates were obtained, with 62 isolates confirmed as <em>Actinomycetes</em> through PCR amplification of the 16S rRNA gene. Approximately 46.5% of these isolates exhibited antibacterial activity, with pronounced effects against <em>B. cereus</em> and <em>S. aureus</em>, suggesting their potential role in combating antibiotic-resistant bacteria. Genetic analysis revealed the presence of non-ribosomal peptide synthetase (<em>NRPS</em>) genes, indicating that the produced antimicrobial compounds may originate from NRPS pathways. However, no polyketide synthase (<em>PKS</em>) genes were detected, which may limit the diversity of bioactive metabolites. These findings highlight the pharmaceutical potential of hollyhock-associated <em>Actinomycetes</em> as promising sources of novel antimicrobial agents.https://mmb.irost.ir/article_1508_92987d9bb11d34389981c961b5a75a4c.pdfIranian Research Organization for Science and Technology (IROST)Microbiology, Metabolites and Biotechnology2980-88557220241201Enhanced Expression of an Acinetobacter baumannii specific recombinant endolysin in Escherichia coli102108150910.22104/mmb.2025.7277.1159ENFatemehKhosravi NodeDepartment of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, IranNahidBakhtiariDepartment of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, IranSomayeImanparastDepartment of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, IranDavoodZareDepartment of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, IranJournal Article20241221Prophage endolysin PlyF307, a peptidoglycan-destroying enzyme previously identified through the screening of the Acinetobacter baumannii genome, has shown the ability to kill numerous clinical isolates of <em>A. baumannii</em> in its recombinant form. <em>A. baumannii</em> is an extremely antibiotic-resistant Gram-negative hospital pathogen that is distributed worldwide. In this study, we used <em>Escherichia coli</em> BL21(DE3) and BL21(DE3) pLysS as a recombinant protein expression host to produce His-tagged PlyF307. Expression was done in Luria-Bertani (LB), Terrific Broth (TB), and auto-inducing medium, and different concentrations of β- d-1-thiogalactopyranoside (IPTG) were used for inducing. Induction was performed several times during the logarithmic growth phase. Bacterial cells were harvested at different post-induction times. Extraction and purification of the recombinant endolysin were performed using different lysis buffers and sonication programs. According to the experimental results, expression inducing was done with 0.1 mM IPTG at OD<sub>600</sub> = 0.9. The incubation temperature was 37 °C before and after the induction time. Finally, 520-570 mg of recombinant his-tagged PlyF307 (19.7 kD) was purified in different batches using 250 mM imidazole from 8- h post-induction harvested <em>E.coli</em> BL21(DE3) pLysS- PlyF307 cultured in 1- l Luria- Bertani broth (LB) medium in baffled flasks. The purified recombinant protein was verified using the western blotting technique. In conclusion, the strong positive net charge and bacteriolytic activity of the PlyF307 make it a suitable candidate for use in therapeutics and other biotechnology applications. Enhancement of the recombinant endolyzin production yield was considerable in this study and will be helpful to achieve this purpose, and this improved expression can be a significant step toward the scaling-up of the enzyme production in <em>E. coli</em>.https://mmb.irost.ir/article_1509_302b507404db5167729cc6e34138147c.pdfIranian Research Organization for Science and Technology (IROST)Microbiology, Metabolites and Biotechnology2980-88557220241201Microbial Preservation Efficacy of Dacron Swabs: A Study on Freeze-Drying vs. Conventional Drying for Bacterial Viability109115153810.22104/mmb.2025.7297.1158ENSomayeMakzumMicroorganisms Bank, Iranian Biological Resource Centre (IBRC), ACECR, Tehran, IranRezaHaghshenasMicroorganisms Bank, Iranian Biological Resource Centre (IBRC), ACECR, Tehran, IranShokufehRafieyanMicroorganisms Bank, Iranian Biological Resource Centre (IBRC), ACECR, Tehran, IranMahdiMoshtaghi NikouMicroorganisms Bank, Iranian Biological Resource Centre (IBRC), ACECR, Tehran, IranJournal Article20241221In general, microbiological and biotechnological research depend significantly on microbial preservation. Researchers and medical professionals have used swabs to transfer and preserve clinical specimens for many years. Studies have demonstrated that the synthetic fiber Dacron has a high sample release rate, which is essential for the effectiveness of bacteriological and molecular tests, including the collection of bacterial samples. This study evaluated the recovery of five commonly referenced bacteria: <em>Lacticaseibacillus casei</em> IBRC-M 10711, <em>Bacillus subtilis </em>subsp. <em>subtilis</em> IBRC-M 10997, <em>Salmonella enterica</em> subsp. <em>enterica</em> IBRC-M 10707, <em>Staphylococcus aureus</em> subsp. <em>aureus</em> IBRC-M 10917, and <em>Streptococcus mutans</em> IBRC-M 10682 after preservation on Dacron swabs using standard microbiological assays. The ability of Dacron swabs to retain viable bacteria following two drying methods, freeze-drying and conventional drying methods, and the bacteria recovery was monitored for one year. The results showed that all five bacteria maintained their viability for three months by freeze-drying and conventional drying methods, with no discernible differences between them according to comparing viability percentage.<em> </em>Among tested bacteria, only <em>B. subtilis</em> and <em>L. casei</em> were effectively recovered from the Dacron swabs maintained at 4 °C after one year. <em>B. subtilis</em> was recovered after one year when preserved by both drying methods. In contrast, <em>L. casei</em> sustained viability only with the freeze-drying process. So, for medium-term bacterial preservation (up to three months), conventional drying methods are a cost-effective and straightforward approach for preserving bacteria on Dacron swabs; however, for long-term preservation, one-year results indicate that the type of strain may have a major impact on how effectively bacteria can be preserved using this method. Therefore, more strains must be assessed before an ultimate decision on the method's suitability for long-term preservation can be made.https://mmb.irost.ir/article_1538_d7f8a720aed1bda373bede1bf2ea5ca7.pdfIranian Research Organization for Science and Technology (IROST)Microbiology, Metabolites and Biotechnology2980-88557220241201Postbiotics: A New Approach from Gut Health to Cancer Therapy116137154710.22104/mmb.2025.7409.1164ENParastooSanieeDepartment of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranShahrzadAsgariDepartment of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranPariaGhadersoltaniDepartment of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranSomayyehSeyyedzadeh NiriDepartment of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranShayanImaniDepartment of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranHaleRostamiDepartment of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranAylarShabaniDepartment of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranZahraRajabi FardDepartment of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranJournal Article20250310Recent research has increasingly highlighted the potential of postbiotics, non-viable microbial metabolites and cellular components, in enhancing human health, particularly through gut microbiota modulation and cancer therapy. Unlike probiotics, postbiotics offer advantages such as improved stability, safety, and ease of standardization. Their ability to provide therapeutic benefits without the risks associated with live microbes makes them promising candidates for clinical applications, as cancer adjuvants, and functional food applications. These bioactive compounds can enhance treatment outcomes and reduce side effects by exhibiting multiple anti-cancer mechanisms, including disrupting carcinogenic pathways, enhancing gut barrier integrity, and reducing inflammation. Evidence from in vitro and in vivo studies demonstrates their potential against various cancers, including colorectal, breast, gastric, and liver cancers. Despite these promising preclinical results, several challenges hinder their clinical translation, including variability in formulations, lack of standardized production methods, and limited clinical trials to confirm efficacy and safety. This review provides a comprehensive overview of the evolving definitions, classifications, and sources of postbiotics, as well as the mechanisms through which they may influence cancer development and progression, and highlights additional health benefits they confer. Moreover, it underscores the critical need for further research to identify specific bioactive compounds, optimize delivery systems, and establish safety profiles through rigorous clinical investigations. Harnessing postbiotics could revolutionize cancer prevention and treatment strategies, offering safe, effective, and adjunctive therapeutic options that integrate with personalized medicine and functional nutrition.https://mmb.irost.ir/article_1547_0cea193ac4be2be12ae672f11fd9dac0.pdf