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Hari Krishnan K, PhD

Scientist E-I

+91-471-2529523

harikrishnan@rgcb.res.in

harikrishnan
harikrishnan

Hari Krishnan K, PhD

Scientist E-I

+91-471-2529523

harikrishnan@rgcb.res.in

  • Profile

    • PhD Aquatic Biology (University of Kerala)
    • MSc Zoology (Kanpur University)
    • 2006 onwards, Scientist C
    • 2001-2006: Scientist B, Rajiv Gandhi Centre for Biotechnology
    • 1996-2001: Postdoctoral Fellow, Rajiv Gandhi Centre for Biotechnology
    • 1994-1996: Research Assistant, Rajiv Gandhi Centre for Biotechnology
    • Life member, National Institute of Ecology (NIE), India
    • Life Member, Marine Biological Association of India
    • Life Member, Biotech Research Society of India
    • Life Member, National Environmental Science Academy (NESA), India
    • Nominated member, State Level Expert Appraisal Committee (SEAC), Kerala by Ministry of Forest and Environment, Govt of India
  • Research

    Metagenomics

    Microorganisms dominate the biosphere. Current methods of culture reveal less than 1% of the microbial diversity. The new approach is the culture-independent analysis of a mixture of microbial genomes (metagenomics) based on expression or sequencing. The hidden microbial diversity is an inexhaustible source for new valuable products such as industrial enzymes, antimicrobials and therapeutic agents and also source for novel genes for biodegradation. New enzymes could potentially be useful to many industrial applications, and new antimicrobial drugs are becoming increasingly important.

    1. Bioprospecting the mangrove and estuarine metagenomes
      The study envisages construction of metagenomic libraries from the estuarine and mangrove environment, using expression cloning. These libraries will be screened by functional assay for the presence of genes for important industrial enzymes, antimicrobial agents and therapeutic enzymes. The discovered genes will be sequenced and compare with currently known sequences, to identify novel genes. This approach will help in the isolation of novel genes for the production of new enzymes applicable in industries or that may give rise to new antimicrobial compounds, through mining the genomes of microorganisms of diverse environmental origin without culturing them.
    2. Assessing bacterial diversity by generating 16SrRNA clone library
      Our knowledge on the bacterial diversity in different environments is limited, since many of them cannot be cultured by current culture-based traditional methods. Molecular approaches have greatly enhanced the knowledge of population structure in natural microbial communities. In our study, we try to analyze the complex genomes of microbial niches through culture-independent molecular techniques by generating 16S rRNA clone library along with RFLP, sequencing and phylogenetic analysis
    3. Diversity of methanotrophs in wetland ecosystems
      Climate has far reaching impacts on biological systems in the biosphere. The Earth is already experiencing sufficient climate change to affect biological systems and predicting future biological impacts of climate change remains a formidable challenge. Microbes act as climate engineers by playing the pivotal role in geochemical cycles. Wetlands are important ecosystems in the methane cycle. Methane-oxidizing bacteria in these ecosystems serve as a methane filter and limit methane emissions, one of the crucial factors responsible for global warming and climate change. Yet little is known about the diversity of the methanotrophs present in wetlands, and only a few isolates are known. The study envisages assessing the biodiversity of methanotrophic communities from the wetland ecosystems in Kerala through metagenoomic approach targeting the 16S rRNA gene and certain selected functional genes.
    4. Metagenomic analysis of gut microbiome from type 2 diabetic subjects in Kerala
      The human gastrointestinal environment harbours a complex microbial ecosystem. Accumulating evidence shows that human gut microbiota plays intricate and key roles in health and disease. Characterization of the gut microbiota has been hindered by the refractory cultivation of most species. Metagenomic analysis of the gut microbiome will provide insight into the genetic potential and diversity of complex microbial communities, including uncultured species. The studies on the gut microbiota of Indian population are meagre. The incidence of diabetes in Indian population and particularly in Kerala population is showing and increasing trend. Hence, it is worthwhile to look into the role of gut microbiota as an etiology in high incidence of diabetes apart from the lifestyle and genetic predisposition. The investigation is an attempt to analyse the diversity and function of the gut microbiota from type 2 diabetic patients though metagenomic approach.

    Microbial production of Polyhydroxybutyric acid (PHB)

    PHB [Poly(3-hydroxybutyric acid)] is a biodegradable thermoplastic accumulated by several microorganisms as carbon and energy reservoir. They are immunologically compatible with human tissue and can be used as biodegradable carriers for controlled drug release and are currently used in industry and medicine. The main limitations for the bulk production of bioplastics are its high production and recovery costs. Generation of recombinant organisms for the biosynthesis of PHB will improve the yields of production and reduce the costs. We have isolated several bacteria producing PHB from various environments in Kerala. The PHB gene cluster from a bacterial strain which exhibited high efficiency in PHB production have been amplified. Presently we are focusing on cloning and expression of PHB genes.

    Microbial fuel cells for wastewater treatment and energy production

    Microbial fuel cells hold great promise as a sustainable biotechnological solution to future energy needs and wastewater treatment process. A microbial fuel cell converts chemical energy into electricity through the catabolic activities of microorganisms. Current efforts to improve the efficiency of such fuel cells are limited by the lack of knowledge about the microbial ecology of these systems.The study aims to elucidate the exoelectrogenic bacterial community from different environment and their potential in wastewater treatment and energy production.

    Completed and ongoing projects

    1. Generation of metagenomic libraries forscreening novel bioactive compounds (Principal Investigator), Kerala State Council for Science Technology and Environment, Govt. of Kerala, 2008 - 2009 (Rs. 4 lakhs)
    2. A novel site specifically targeting nanoparticle based oral-drug and siRNA releasing polymer systems for colon cancer (Co-Investigator), DBT, Govt. India 2010-2013 (Rs. 1.22 crores)
    3. Studies on the distribution and diversity of methanotrophic microbial communities mitigating methane emission in Kuttanad wetland ecosystem - Kerala (Principal Investigator), Department of Environment and Climate Change, Govt. of Kerala, 2013-2016 (Rs.11.27 lakhs)
    4. Metagenomic analysis of gut microbiome from type 2 diabetic subjects in Kerala - a preliminary study, Kerala State Council for Science Technology and Environment, Govt. of Kerala, 2013-2016 (Rs. 21.65 lakhs)
    • Dr. G. S. Vinod Kumar, Chemical Biology, RGCB
    • Dr. Abdul Jaleel. K. A, Cardiovascular Disease Biology, RGCB
  • Publications

    1. Arjun J.K and Harikrishnan K (2011) Metagenomic analysis of bacterial diversity in the rice rhizosphere soil microbiome. Biotechnol. Bioinf. Bioeng., 1(3):361-367
    1. Vidhya M.K, Sandhya C Nair, Geetha S. L and HariKrishnan K Assessing estuarine biofilm bacterial diversity by 16S rRNA clone library - A metagenomic approach. MECOS 09, International Symposium on Marine Ecosystems Challenges and Opportunities, February 9 -12, 2009, Kochi, Kerala.
    2. Vidhya M.K and HariKrishnan K Screening environmental genomic library for catabolic genes involved in phenol bioremediation, National Conference on Biotechnology for Human Development, November 27 – 28, 2009, VIT University, Vellore Tamil Nadu.
    3. Metagenomics – a pursuit to expose the unexplored microbial diversity. Winter school on bioinformatics, December 14, 2009, KAU, Vellanikkara, Thrissur, Kerala. Organised by Bioinformatics Centre, KAU, Thrissur
    4. HariKrishnan K 2010. Bacterial diversity in a microbial fuel cell: The green energy technology - A metagenomic perspective. International Conference on " The Green Path to Sustainability: Prospects and Challenges" GREPSPAC-2010, July 7 - 9, 2010, Changanacherry, Kerala
    5. Arjun J.K and HariKrishnan K (2011) Metagenomic analysis of bacterial diversity in the rice rhizosphere soil microbiome. National Symposium on "Innovative and Modern Technologies for Agricultural Productivity, Food Security and Environmental Management" 22-23 July 2011, Mangalore.
    6. Arjun J.K, Aneesh B. and HariKrishnan K (2012). Production and characterization of Penicillin G Acylase from a Bacillus sp. isolated from forest soil. 2nd National symposium on Innovative and Modern Technologies for Agricultural Productivity, Food Security and Environment Management,19-20November, 2012, Thrissur, India
    7. Aneesh B, Arjun J.K and HariKrishnan K (2012).Cloning and Characterization of PHA Synthase Gene (phaC) of Bacillus sp. isolated from the environment. 53 rd Annual conference of Association of Microbiology of India, International Conference on Microbial World: Recent innovations and future trends, 22-25 November, 2012, Bhubaneswar, India
    8. Arjun J.K, Aneesh B. and HariKrishnan K (2013). Partial purification and characterization of L-Asparaginase from soil metagenomic library. International Conference on Advances in Biotechnology and Patenting, 18-21February, 2013, Trichy, India.
    9. Kavitha T and HariKrishnan K (2013). A PCR based system for detection of methanotrophic bacteria from environment. 54th Annual conference of Association of Microbiology of India (AMI) International conference on Frontier discoveries and innovations in Microbiology and its interdisciplinary relevance (FDMIR-2013) 17-20 November 2013, Maharshi Dayanand University Rohtak, Haryana
    10. Arjun J. K and HariKrishnan K (2013). Production and characterization of therapeutic L- asparaginase from a Marinononas sp. isolated from marine sediments. 54th Annual conference of Association of Microbiology of India (AMI) International conference on Frontier discoveries and innovations in Microbiology and its interdisciplinary relevance (FDMIR-2013) 17-20 November 2013, Maharshi Dayanand University Rohtak, Haryana.
    11. Aneesh B and HariKrishnan K (2013). Cloning and characterization of NADPH- dependent acetoacetyyl- CoA dehydrogenase gene (pha B) from Bacillus megaterium isolated from the environment. 54th Annual conference of Association of Microbiology of India (AMI) International conference on Frontier discoveries and innovations in Microbiology and its interdisciplinary relevance (FDMIR-2013) 17-20 November 2013, Maharshi Dayanand University Rohtak, Haryana

    GenBank DNA sequences

    1. Hari Krishnan K and Vidhya M.K Bacteria associated with marine intertidal floral assemblages from the Kerala coast, India (16S rRNA gene sequences of Bacillus pumilus strain TV-18 (Acc. No. HQ386703); Bacillus aquimaris strain VZ-24 (Acc. No. HQ386704); Bacillus firmus strain VZ-56 (Acc. No. HQ386705) (2010)
    2. Mathew B.R, Kesavankutty V and Krishnan H Studies on the diversity and molecular phylogeny of bacteria from the coconut husk retting soil, Kerala, south India(16S rRNA gene of uncultured bacterium clones. Acc Nos. HM357253, HM357254, HM231166) (2010)
    3. Mathew B.R. and Hari Krishnan K. Studies on the bacterial diversity in the coconut husk retting zone, Kerala, India (16S rRNA gene of uncultured bacterium clones. Acc Nos. HQ845885 to HQ845920 - 36 sequences) (2011)
    4. John F.A. and Harikrishnan K. Prevalence of genes conferring beta-lactam resistance in the coconut husk retting zone, Kerala, India (Beta-lactamase (bla) gene of uncultured bacterium clones. (Acc Nos. JN561601 and JN561602) (2011)
    5. John F.A and Harikrishnan K Studies on the archaeal diversity in the coconut husk retting zone, Kerala, India (16S rRNA gene of uncultured archaeal clones. (Acc Nos. JN408852 to JN408871 - 20 sequences) (2011)
    6. Arjun J.K, Aneesh B , Bijoynandan S and Harikrishnan K Prevalance of beta-lactam resistance genes in Arctic soil. Uncultured soil bacterium clones beta-lactamase (bla) gene, partial cds. (Acc Nos. KC428420 to KC428432 - 13 sequences) (2012)
    7. Aneesh B, Arjun J.K, Kavitha T and Hari Krishnan K Cloning, expression and characterization of NADPH-dependent acetoacetyl-CoA dehydrogenase gene (phaB) from Bacillus sp. (16S rRNA gene sequences of Bacillus aryabhattai strain PHB10 (Acc. No. KF056892); Bacillus megaterium PHB29 (KF056893) (2013)
    8. Arjun J.K , Aneesh B , Kavitha T and Hari Krishnan K L-asparaginase production by halophilic bacteria isolated from marine sediments of Kerala(16S rRNA gene sequences, Acc. Nos. KF142387 to KF142396) (2013)
    9. Aneesh B, Arjun J.K, Kavitha T and Hari Krishnan,K Cloning, Expression and Characterization of NADPH-dependent acetoacetyl-CoA dehydrogenase gene (phaB) from Bacillus sp. (Acetoacetyl-CoA reductase (phaB)gene, complete cds. (Acc. Nos. KF155284 and KF155285) (2013).
    10. Arjun J.K, Aneesh B and Hari Krishnan K Generation of metagenomic library and screening for potential enzymes. (Uncultured Serratia sp. 16S ribosomal RNA gene, partial sequence, Acc. No. KF155286) (2013)
  • Team


    Arjun J K, PhD Student (UGC-SRF)

    Generation of metagenomic libraries and screening for potential biomolecules

    Interested in exploring the metagenomes of the natural environments like estuaries, mangroves and forests of Kerala, which are biodiversity hotspots. The studies will lead to the discovery of novel natural products like therapeutic enzymes encoded by the genomes of previously uncultured microorganisms, which represents more than 99% of the microbes present in any environment. I am focussing on therapeutic enzymes especially L-asparaginase, an anti-neoplastic agent used in the chemotherapy of Acute Lymphoblastic Leukemia and Lymphosarcoma in humans for the last 25 years. All the reported L- Asparaginase so far is from less than 1% of culturable microorganisms present in the environment and the vast majority of the uncultivable fraction is still unexplored.

    Arjun J.K
    Arjun J.K

    Arjun J K, PhD Student (UGC-SRF)

    Generation of metagenomic libraries and screening for potential biomolecules

    Interested in exploring the metagenomes of the natural environments like estuaries, mangroves and forests of Kerala, which are biodiversity hotspots. The studies will lead to the discovery of novel natural products like therapeutic enzymes encoded by the genomes of previously uncultured microorganisms, which represents more than 99% of the microbes present in any environment. I am focussing on therapeutic enzymes especially L-asparaginase, an anti-neoplastic agent used in the chemotherapy of Acute Lymphoblastic Leukemia and Lymphosarcoma in humans for the last 25 years. All the reported L- Asparaginase so far is from less than 1% of culturable microorganisms present in the environment and the vast majority of the uncultivable fraction is still unexplored.

    Aneesh B, PhD Student (CSIR-JRF)

    Cloning and expression of Polyhydroxybutyrate (PHB) biosynthesis genes from bacteria

    Polyhydroxybutyrate (PHB) is one of water-insoluble, biodegradable, storage polymers in bacteria. The thermoplastic and elastomeric properties of them, which resemble those of petroleum-based plastics and its biodegradability and biocompatibility, have increased their application potential. The presence of the PHB depolymerase enzyme in natural PHB producers, prevents their current use in the industrial production of the bioplastics. Cloning the biosynthetic gene cluster without depolymerase gene into an easily manageable bacterial system may make the industrial production of bioplastics more efficient and economical. My study aimed at the isolation and screening of bacteria with high PHB productivity, cloning the PHB biosynthetic genes, and optimization of the polymer production and its properties.

    Aneesh  B
    Aneesh  B

    Aneesh B, PhD Student (CSIR-JRF)

    Cloning and expression of Polyhydroxybutyrate (PHB) biosynthesis genes from bacteria

    Polyhydroxybutyrate (PHB) is one of water-insoluble, biodegradable, storage polymers in bacteria. The thermoplastic and elastomeric properties of them, which resemble those of petroleum-based plastics and its biodegradability and biocompatibility, have increased their application potential. The presence of the PHB depolymerase enzyme in natural PHB producers, prevents their current use in the industrial production of the bioplastics. Cloning the biosynthetic gene cluster without depolymerase gene into an easily manageable bacterial system may make the industrial production of bioplastics more efficient and economical. My study aimed at the isolation and screening of bacteria with high PHB productivity, cloning the PHB biosynthetic genes, and optimization of the polymer production and its properties.

    Kavitha T, Project Fellow

    Studies on the distribution and diversity of methanotrophs in wetland ecosystems

    Methanotrophs are significant microbial population helps in the mitigation of global methane load, one of the crucial factors responsible for global warming and climate change. My objective is to study the diversity of methanotrophic microbial communities present in Kuttanad wetland ecosystem, Kerala through culture independent approaches by generating and sequencing metagenomic libraries of 16S rRNA gene and certain selected functional genes unique to methanotrophs.

    Kavitha  T
    Kavitha  T

    Kavitha T, Project Fellow

    Studies on the distribution and diversity of methanotrophs in wetland ecosystems

    Methanotrophs are significant microbial population helps in the mitigation of global methane load, one of the crucial factors responsible for global warming and climate change. My objective is to study the diversity of methanotrophic microbial communities present in Kuttanad wetland ecosystem, Kerala through culture independent approaches by generating and sequencing metagenomic libraries of 16S rRNA gene and certain selected functional genes unique to methanotrophs.

    Silju Juby, Project Fellow

    Metagenomic analysis of gut microbiome from type 2 diabetic subjects in Kerala

    Human gastrointestinal tract harbours a complex microbial ecosystem. Accumulating evidence shows that human gut microbiota plays intricate and key roles in our health and disease. Assessment and characterization of gut microbiota has become a major research area in human disease, including type 2 diabetes, the most prevalent endocrine disease worldwide. Characterization of the gut microbiota has been hindered by the refractory cultivation of most species. In the present study I am focusing on the culture-independent metagenomic approach for the characterization of the human gut microbiome in type 2 diabetic population in Kerala.

    Silju_Profile Pic_final
    Silju_Profile Pic_final

    Silju Juby, Project Fellow

    Metagenomic analysis of gut microbiome from type 2 diabetic subjects in Kerala

    Human gastrointestinal tract harbours a complex microbial ecosystem. Accumulating evidence shows that human gut microbiota plays intricate and key roles in our health and disease. Assessment and characterization of gut microbiota has become a major research area in human disease, including type 2 diabetes, the most prevalent endocrine disease worldwide. Characterization of the gut microbiota has been hindered by the refractory cultivation of most species. In the present study I am focusing on the culture-independent metagenomic approach for the characterization of the human gut microbiome in type 2 diabetic population in Kerala.

    Geetha S.L, Project Assistant

    Geetha  S. L
    Geetha  S. L

    Geetha S.L, Project Assistant

  • Alumni