توليد بيوسورفكتانت توسط لاكتيك اسيد باكتري لاكتوباسيلوس پلانتاروم با استفاده از منابع مغذي مناسب

Biosurfactant Production by Lactic Acid Bacterium Lactobacillus plantarum Using Appropriate Nutrient Sources

ﺑﯿﻮﺳﻮرﻓﮑﺘﺎﻧﺖﻫﺎ ﻣﺘﺎﺑﻮﻟﯿﺖﻫﺎي )ﻋﻤﺪﺗﺎ ً ﺛﺎﻧﻮﯾﻪ( ﺗﻮﻟﯿﺪﺷﺪه ﺗﻮﺳﻂ ﻣﯿﮑﺮوارﮔﺎﻧﯿﺰمﻫﺎ ﻫﺴﺘﻨﺪ ﮐﻪ ﺑﻪدﻟﯿﻞ داراﺑﻮدن وﯾﮋﮔﯽﻫﺎي ﺳﻮدﻣﻨﺪ ﻓﺮاوان، از ﻗﺎﺑﻠﯿﺖﻫﺎي ﺑﺎﻟﻘﻮه و ﮐﺎرﺑﺮدي ﮔﺴﺘﺮدهاي در ﺻﻨﺎﯾﻊ ﻣﺨﺘﻠﻒ ﺑﺮﺧﻮردارﻧﺪ. ﻋﻠﯽرﻏﻢ ﻣﺰاﯾﺎي ﺑﺴﯿﺎر، ﺑﻪ دﻻﯾﻞ ﻓﻨﯽ و اﻗﺘﺼﺎدي از ﺟﻤﻠﻪ راﻧﺪﻣﺎن ﭘﺎﯾﯿﻦ، ﻫﺰﯾﻨﻪ ﺑﺎﻻي ﺗﻮﻟﯿﺪ و ﻓﺮآوري و ﻧﻮع ﺳﻮﯾﻪﻫﺎي ﺗﻮﻟﯿﺪﮐﻨﻨﺪه، اﺳﺘﻔﺎده ﺗﺠﺎري از ﺑﯿﻮﺳﻮرﻓﮑﺘﺎﻧﺖﻫﺎ ﺑﻪوﯾﮋه در ﺻﻨﺎﯾﻊ ﻏﺬاﯾﯽ و داروﯾﯽ ﻣﺤﺪود اﺳﺖ. اﮐﺜﺮ ﻣﯿﮑﺮوارﮔﺎﻧﯿﺰمﻫﺎي ﺗﻮﻟﯿﺪﮐﻨﻨﺪه ﺑﯿﻮﺳﻮرﻓﮑﺘﺎﻧﺖﻫﺎ ﮐﻪ ﺗﺎﮐﻨﻮن ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪاﻧﺪ، ﺳﻮﯾﻪﻫﺎﯾﯽ ﺑﯿﻤﺎريزا ﻫﺴﺘﻨﺪ ﮐﻪ ﮐﺎرﺑﺮد ﺑﯿﻮﺳﻮرﻓﮑﺘﺎﻧﺖ ﺧﺎم ﺣﺎﺻﻞ از آﻧﻬﺎ در ﻣﺼﺎرف ﺻﻨﻌﺘﯽ و زﯾﺴﺖﻣﺤﯿﻄﯽ ﺑﻪوﯾﮋه در ﺻﻨﺎﯾﻊ ﻏﺬاﯾﯽ، داروﯾﯽ، آراﯾﺸﯽ و ﺑﻬﺪاﺷﺘﯽ ﺑﻪراﺣﺘﯽ ﻗﺎﺑﻞ ﭘﺬﯾﺮش ﻧﺨﻮاﻫﺪ ﺑﻮد. از اﯾﻦ رو، ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ ﺑﺎ ﻫﺪف ارزﯾﺎﺑﯽ و ﺗﻮﻟﯿﺪ ﺣﺪاﮐﺜﺮي ﺑﯿﻮﺳﻮرﻓﮑﺘﺎﻧﺖ ﻣﺘﺼﻞ ﺑﻪ ﺳﻠﻮل ﺗﻮﺳﻂ ﻻﮐﺘﯿﮏاﺳﯿﺪﺑﺎﮐﺘﺮي ﻻﮐﺘﻮﺑﺎﺳﯿﻠﻮس ﭘﻼﻧﺘﺎروم (ATCC 8014) از ﻃﺮﯾﻖ ﺗﻐﯿﯿﺮ و ﺑﻬﯿﻨﻪﺳﺎزي ﻣﯿﺰان ﻣﻨﺒﻊ ﮐﺮﺑﻨﯽ اﺻﻠﯽ ﻣﺤﯿﻂ ﮐﺸﺖ ﻣﯿﮑﺮوﺑﯽ اﺧﺘﺼﺎﺻﯽ اﻧﺠﺎم ﮔﺮﻓﺘﻪ اﺳﺖ. ﺑﺪﯾﻦ ﻣﻨﻈﻮر، ﺳﻪ ﺗﺮﮐﯿﺐ ﻣﺤﯿﻂ ﮐﺸﺖ ﺑﺎ ﻣﯿﺰان ﮔﻠﻮﮐﺰ ﻣﺘﻔﺎوت، از ﻧﻈﺮ ﺗﻮﻟﯿﺪ ﺗﻮده ﺳﻠﻮﻟﯽ و ﺑﯿﻮﺳﻮرﻓﮑﺘﺎﻧﺖ ﮐﻪ ﻣﻘﺪار آن ﺑﺎ ﻣﻌﯿﺎر ﻣﯿﺰان ﮐﺎﻫﺶ ﮐﺸﺶ ﺳﻄﺤﯽ ﺑﺎﻓﺮ ﻧﻤﮑﯽ ﻓﺴﻔﺎت ﺳﻨﺠﯿﺪه ﻣﯽﺷﻮد در ﻓﻼﺳﮏﻫﺎي ﻫﻢﺧﻮرﻧﺪه و ﻫﻤﭽﻨﯿﻦ در ﺑﯿﻮراﮐﺘﻮر ﻏﯿﺮﻣﺪاوم ﺗﺤﺖ ﺷﺮاﯾﻂ دﻣﺎ، pH و ﺳﺮﻋﺖ ﻫﻢزدن ﮐﻨﺘﺮلﺷﺪه ﻣﻮرد ارزﯾﺎﺑﯽ ﻗﺮار ﮔﺮﻓﺘﻨﺪ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﺗﺨﻤﯿﺮ ﻫﻢ در آزﻣﺎﯾﺸﺎت ﻣﺮﺑﻮط ﺑﻪ ﻓﻼﺳﮏﻫﺎ و ﻫﻢ در ﺑﯿﻮراﮐﺘﻮر، ﻧﺸﺎندﻫﻨﺪه ﺣﺪاﮐﺜﺮ ﻏﻠﻈﺖ ﺗﻮده ﺳﻠﻮﻟﯽ )3/92 و 4/17ﮔﺮم ﺑﺮ ﻟﯿﺘﺮ( و ﺣﺪاﻗﻞ ﮐﺸﺶ ﺳﻄﺤﯽ )41/17 و 40/48ﻣﯿﻠﯽﻧﯿﻮﺗﻦ ﺑﺮ ﻣﺘﺮ( و درﻧﺘﯿﺠﻪ ﺣﺪاﮐﺜﺮ ﻣﯿﺰان ﺑﯿﻮﺳﻮرﻓﮑﺘﺎﻧﺖ ﺗﻮﻟﯿﺪي در ﻣﺤﯿﻂ ﮐﺸﺖ ﺣﺎوي 30ﮔﺮم ﺑﺮ ﻟﯿﺘﺮ ﮔﻠﻮﮐﺰ اﺳﺖ. ﻫﻤﭽﻨﯿﻦ، ﻃﯿﻒﺳﻨﺠﯽ ﺗﺒﺪﯾﻞ ﻓﻮرﯾﻪ ﻣﺎدون ﻗﺮﻣﺰ ﻧﺸﺎن داد ﮐﻪ ﺑﯿﻮﺳﻮرﻓﮑﺘﺎﻧﺖ ﺗﻮﻟﯿﺪﺷﺪه ﻣﺨﻠﻮﻃﯽ از ﭘﺮوﺗﺌﯿﻦ، ﭘﻠﯽﺳﺎﮐﺎرﯾﺪ و اﺣﺘﻤﺎﻻً ﮔﺮوه ﻓﺴﻔﺎت و داراي ﺳﺎﺧﺘﺎر ﮔﻠﯿﮑﻮﭘﺮوﺗﺌﯿﻨﯽ اﺳﺖ.

Biosurfactants are (mainly secondary) metabolites produced by microorganisms which have potential capabilities in various industries due to their abundant beneficial properties. In spite of great advantages, commercial utilization of biosurfactants especially in food industry and pharmaceutics is limited for the reasons of technical and commercial problems such as low yield, high production cost, and the type of producing strain. Majority of biosurfactant-producing microorganisms ever evaluated, are pathogenic strains and are not effortlessly acceptable in industrial applications and their products cannot be easily utilized in environmental applications as well as in health and cosmetics, pharmaceuticals and food industries. The present study aims to investigate high production of cell-bound biosurfactant by lactic acid bacterium Lactobacillus plantarum (ATCC 8014) through optimization of the main carbon source of a specific culture medium. Therefore, three culture media with different amounts of glucose were evaluated for biomass and biosurfactants (by surface tension reduction of phosphate-buffered saline) production in shake flasks and bioreactor (controlled temperature, pH and agitating speed). The results from the both shake flasks fermentation and bioreactor showed respectively the maximum biomass concentration of 3.92 and 4.17g/L, the minimum surface tension of 41.17 and 40.48mN/m and subsequently the maximum biosurfactants production in culture medium including 30g/L of glucose. Furthermore, Fourier transform infrared spectroscopy analysis indicated the biosurfactants are structurally a mixture of protein, polysaccharide, and possibly phosphate group, possessing glycoprotein structure.