en بیوتکنولوژی Biotechnology پژوهشي Research <div style="text-align: justify;"><strong>Background:</strong> Vitamin K2 refers to a series of naphthoquinone derivatives, which have a variety of physiological and pharmacological functions for the human body. The most important type of vitamin K2 is menaquinone-7 (MK-7), an expensive raw material with no local manufacturers in Iran.<br> <strong>Objectives:</strong> Since there was no report on the yield of MK-7 produced by the currently available Bacillus subtilis natto species in Iran, this study aims to optimize the culture condition for the production of MK-7 using this Bacillus species.</div> <div style="text-align: justify;"><strong>Materials and Methods: </strong>The base medium (BM) for MK-7 production contained glycerol (6.3%), soybean peptone (3%), and yeast extract (0.51%). The selected factors for optimizing the MK-7 production included the incubation temperature (30, 37, and 40&deg;C) and incubation time (72, 96, and 120hr) with/without the addition of K2HPO4 to the fermentation medium. Three sets of experiments with six modes in each set were designed based on these parameters. MK-7 content was analyzed by the HPLC method.<br> <strong>Results: </strong>Two experiments showed the highest MK-7 production yields of 0.319 and 0.3158 mg/L. The culture condition for both of these yields was as follows:120 hours incubation time in the presence of K2HPO4. However, the incubation temperature was different in these two experiments. The incubation temperature of 30&deg;C resulted in 0.319 mg/L MK-7 concentration, and 37&deg;C yielded 0.3158 mg/L.<br> <strong>Conclusion: </strong><em>B. subtilis</em> natto (IBRC-M 11153) is suitable to be used as a basic platform for the mutation and production of a high-producer species. Optimizing the culture conditions using the wild-type species is not beneficial in increasing the production ability of the bacterium. It is necessary to use different methods for enhancing the production yield of MK-7 to lower the cost of microbial production and make the industrial process economic.<br> &nbsp;</div> Vitamin K2, Bacillus subtilis natto, Menaquinone-7, fermentation 37 46 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-1239-1&slc_lang=en&sid=1 Mohammad Sharifzadeh msharifzadeh@tums.ac.ir 100319475328460010563 100319475328460010563 No Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Negar Mottaghi-Dastjerdi mottaghi.n@iums.ac.ir 100319475328460010564 100319475328460010564 Yes Department of Pharmacognosy and Pharmaceutical Biotechnology, School of Pharmacy, Iran University of Medical Sciences, Tehran, Iran Mohammad Soltany-Rezaee-Rad mohammad.soltany@gmail.com 100319475328460010565 100319475328460010565 No Department of Pharmaceutical Biotechnology and Pharmaceutical Biotechnology Research Center, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Marjan Shariatpanahi shariatpanahi.m@iums.ac.ir 100319475328460010566 100319475328460010566 No Department of Pharmacology and Toxicology, School of Pharmacy, Iran University of Medical Sciences, Tehran, Iran Israa Khalid AL-Yasari asoangel31@gmail.com 100319475328460010567 100319475328460010567 No Department of Pharmacognosy and Pharmaceutical Biotechnology, School of Pharmacy, Iran University of Medical Sciences, Tehran, Iran Sara Noroozi Eshlaghi 100319475328460010568 100319475328460010568 No Department of Pharmacology and Toxicology, School of Pharmacy, Iran University of Medical Sciences, Tehran, Iran. Department of Chemistry, Faculty of Science, University of Zanjan, Zanjan, Iran.