Screening for MCL-PHA-Producing Fluorescent Pseudomonads and Comparison of MCL-PHA Production Under Iso-osmotic Conditions Induced by PEG and NaCl

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• 作者：Ekta Khare (1)
  Jyotsana Chopra (1)
  Naveen Kumar Arora (2)
  
• 刊名：Current Microbiology
• 出版年：2014
• 出版时间：April 2014
• 年：2014
• 卷：68
• 期：4
• 页码：457-462
• 全文大小：474 KB
• 作者单位：Ekta Khare (1)
  Jyotsana Chopra (1)
  Naveen Kumar Arora (2)
  
  1. Department of Microbiology, Institute of Biosciences and Biotechnology, Chhatrapati Shahu Ji Maharaj University, Kanpur, India
  2. Department of Environmental Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
  
• ISSN：1432-0991

文摘

The medium chain length polyhydroxyalkanoates (MCL-PHA) have attracted much attention from academic and industrial communities for their interesting applications in medical field. The aim of this study was to screen high MCL-PHA-producing fluorescent pseudomonads, and to compare the effect of osmotic stress generated by NaCl (ionic) and polyethylene glycol (PEG, non-ionic inert polymer) on PHA production. A total of 50 fluorescent pseudomonads isolated from rhizospheric soil were screened for PHA production by Sudan Black staining. Out of all the PHA-producing isolates only five were MCL-PHA producers as detected by MCL-PCR. Isolate Bar1 identified as Pseudomonas fluorescens by 16S rRNA gene sequencing was selected for further analysis due to its high MCL-PHA production ability. The iso-osmotic stress generated by NaCl and PEG-6000 showed 5.75- and 3.19-fold enhanced production of PHA at ??bar osmotic potential, over control (0?bar), respectively. There was 1.8-fold enhanced production of PHA at ??bar osmotic stress induced by NaCl over PEG. PEG reduces availability of water to microorganisms without reducing exogenously provided nutrients which appear to be responsible for its down performance over NaCl. The FTIR analysis of PHA sample purified from cells showed strong marker bands near 1742, 2870, 1170, 1099, and 2926?cm?, corresponding to MCL-PHA. The study reported that supplementation of NaCl (electrolyte) in growth media enhances the production of MCL-PHA which can be very useful for its industrial production.