Research Interests

BioEthanol Production

Ethanol-Blended-Petrol (EBP) has E3 benefits viz. Economic, Environmental and Energy. India implemented 5% EBP in 2002, proposed to increase to 10% EBP in 2009 and further increase to 20% EBP by 2017. Molasses based ethanol is the only source for ethanol in India. Decline in sugar production in 2008-09 severely affected molasses-ethanol production. Current ethanol production from molasses could meet 5% EBP. To achieve higher ethanol blending other sources are need for ethanol production. Non-food plant sources such as cellulosic plant biomass and sorghum juice are the promising sources to produce bioethanol for EBP program. Our research is focused on process development for economical production of fuel-ethanol from crop residues and sorghum juice.

Functional Oligosaccharides (FOS)

FOS are oligosaccharides with specific physiological functions beyond the basic nutrition. Because of the increasing health problems, caused by stress at work, environmental pollution and unbalanced food in recent days, there have been concerns over functional foods to maintain good health. FOS have lower sweetness than sucrose, high viscosity, low calorific value, resist hydrolysis in gastrointestinal tract and stimulate the proliferation of probiotics, Bifidobacterium sp. and Lactobacillus sp. We are developing economic process for FOS production from plant biomass using enzymes.

Molecular Bioremediation of Cr(VI)

Environmental pollution due to industrialization is the major concern. Heavy metal pollution is a serious issue and chromium is one of the highly toxic metal pollutants. Chromium is emitted to environment from several industrial processes including nuclear power generation. Cr at hexavalent oxidation state is highly toxic to living systems. An efficient way of preventing Cr(VI) pollution is its reduction to Cr(III) which is much less toxic. Biocatalysts such as bacteria and enzymes have the capacity to detoxify Cr(VI) by conversion to Cr(III). Molecular techniques can be employed to improve the bioremediation potential of biocatalysts for application in actual polluted sites. Current research in our lab involves isolation and engineering of enzymes for transformation of Cr(VI) to Cr(III).

Publications

Complete list of publications can be found on Scopus

1. Sana, N.; Arnepalli, D.N.; Krishnan, C. Enhanced Bioconversion of Methane to Biodiesel by Methylosarcina sp. LC-4. Sustainability 2023, 15, 505. DOI

2. Shereena P.JoyChandrarajKrishnan (2022) Industrial Crops and Products. Volume 177, 114409 DOI

3. Gobinath Rajagopalan, Chandraraj Krishnan, (2022) Production of cellulosic butanol by clostridial fermentation: a superior alternative renewable liquid fuel,Ed(s): Baskar Gurunathan, Renganathan Sahadevan, Biofuels and Bioenergy, Elsevier, 2022, Pages 263-289, ISBN 9780323900409,DOI

4. N. Vignesh, K. Chandraraj, S.P. Suriyaraj, R. Selvakumar. (2022) Cellulose A Sustainable Material for Biomedical Applications. Kumar, A., Ram, M., & Singla, Y.K. (Eds.). Advanced Materials for Biomechanical Applications (1st ed.). CRC Press.DOI

5. Bioconversion of animal hair waste using salt- and sulphide-tolerant Bacillus sp. KLP1 and depilation using keratinase Venkatachalam, M., Rathinam, A., Rao, J.R., Krishnan, C.International Journal of Environmental Science and Technology, 2022, 19(7), pp. 63896398

6. Modified organosolv pretreatment for improved cellulosic ethanol production from sorghum biomass Joy, S.P., Krishnan, C.Industrial Crops and Products, 2022, 177, 114409

7. Improved high solids loading enzymatic hydrolysis and fermentation of cotton microdust by surfactant addition and optimization of pretreatmentVignesh, N., Chandraraj, K.Process Biochemistry, 2021, 106, pp. 6069

8. Kinetics and Stoichiometry of an Efficient Methanotroph Methylosarcina sp. LC-4 Isolated from a Municipal Solid Waste Dumpsite Nivedita, S., Arnepalli, D.N., Krishnan, C.Journal of Environmental Engineering (United States), 2021, 147(5), 4021011

9. Facile Fabrication and Characterization of Zn Loaded Cellulose Membrane from Cotton Microdust Waste and its Antibacterial Properties A Waste to Value Approach Vignesh, N., Suriyaraj, S.P., Selvakumar, R., Chandraraj, K. Journal of Polymers and the Environment, 2021, 29(5), pp. 1651 1662

10. Variations in structure and saccharification efficiency of biomass of different sorghum varieties subjected to aqueous ammonia and glycerol pretreatments Joy, S.P., Kumar, A.A., Gorthy, S., …Gaddameedi, A., Krishnan, C. Industrial Crops and Products, 2021, 159, 113072

11. Erratum to Production of xylooligosaccharides from xylan catalyzed by endo-1,4- -D-xylanase-immobilized nanoscale carbon, silica and zirconia matrices [Molecular Catalysis, 484 (2020) 110745] (Molecular Catalysis (2020) 484, (S2468823119306091), (10.1016/j.mcat.2019.110745)) Shivudu, G., Chandraraj, K., Selvam, P. Molecular Catalysis, 2020, 497, 111162

12. Enhanced production of cellulase from a novel strain Trichoderma gamsii M501 through response surface methodology and its application in biomass saccharification Baskaran, R., Krishnan, C.Process Biochemistry, 2020, 99, pp. 48 60

13. Improved co-production of ethanol and xylitol from low-temperature aqueous ammonia pretreated sugarcane bagasse using two-stage high solids enzymatic hydrolysis and Candida tropicalis Raj, K., Krishnan, C. Renewable Energy, 2020, 153, pp. 392 403

14. Production of xylooligosaccharides from xylan catalyzed by endo-1,4- -D-xylanase-immobilized nanoscale carbon, silica and zirconia matrices Shivudu, G., Chandraraj, K., Selvam, P.Molecular Catalysis, 2020, 484, 110745

15. One pot facile green synthesis of crystalline bio-ZrO2 nanoparticles using Acinetobacter sp. KCSI1 under room temperature Suriyaraj, S.P., Ramadoss, G., Chandraraj, K., Selvakumar, R.Materials science & engineering. C, Materials for biological applications, 2019, 105, pp. 110021

16. One pot facile green synthesis of crystalline bio-ZrO2 nanoparticles using Acinetobacter sp. KCSI1 under room temperature Shanmugasundaram Prema, S., Govindarajan, R., Krishnan, C., Rajendran, S.Materials Science and Engineering C, 2019, 105, 110021

17. Immobilization of Recombinant Endo-1,4–xylanase on Ordered Mesoporous Matrices for Xylooligosaccharides Production Shivudu, G., Khan, S., Chandraraj, K., Selvam, P.ChemistrySelect, 2019, 4(38), pp. 11214 11221

18. Improved high solid loading enzymatic hydrolysis of low-temperature aqueous ammonia soaked sugarcane bagasse using laccase-mediator system and high concentration ethanol production Raj, K., Krishnan, C.

19. Bioutilization of poultry feather for keratinase production and its application in leather industry Santha Kalaikumari, S., Vennila, T., Monika, V., …Gunasekaran, P., Rajendhran, J. Journal of Cleaner Production, 2019, 208, pp. 4453

20. Kanak Raj and Chandraraj, K. (2018) High sugar yields from sugarcane (Saccharum officinarum) bagasse using low-temperature aqueous ammonia pretreatment and laccase-mediator assisted enzymatic hydrolysis. Industrial Crops and Products. 111: 673-683.

21. Swain MR, Natarajan V, Krishnan C. (2017) Marine Enzymes and Microorganisms for Bioethanol Production. Advances in Food and Nutrition Research. 80: 181-197.

22. Reddy SS, Chandraraj, K. (2016) Production of xylooligosaccharides in SSF by Bacillus subtilis KCX006 producing –xylosidase-free endo-xylanase and multiple xylan debranching enzymes. Preparative Biochemistry and Biotechnology. 46: 49-55.

23. Sarangi A, Chandraraj, K. (2016) Detoxification of hexavalent chromium by Leucobacter sp. uses a reductase with specificity for dihydrolipoamide. Journal of Basic Microbiology. 56: 175-183.

24. Reddy SS, Chandraraj, K. (2016) Production of high-pure xylooligosaccharides from sugarcane bagasse using crude b-xylosidase-free xylanase of Bacillus subtilis KCX006 and their bifidogenic function. LWT - Food Science Technology. 65: 237-245.

25. Swain MR, Chandraraj, K. (2015) Improved conversion of rice straw to ethanol and xylitol by combination of moderate temperature ammonia pretreatment and sequential fermentation using Candida tropicalis. Industrial Crops and Products. 77: 1039-1046

26. Shyam S. Reddy and Chandraraj, K. (2013) Characterization of enzyme released antioxidant phenolic acids and xylooligosaccharides from different graminaceae or poaceae members. Food Biotechnology, 27:357-370.

27. Elangovan & Ligy Philip and Chandraraj, K. (2010) Hexavalent Chromium Reduction by Free and Immobilized Cell-free Extract of Arthrobacter rhombi-RE. Applied Biochemistry and Biotechnology. 160: 81-97.

28. Gobinath, R., and Chandraraj, K. (2010) Hyper-production of alpha-amylase from agro-residual medium with high-glucose in SSF using catabolite derepressed Bacillus subtilis KCC103. Journal of Basic Microbiology. 50: 336-343.

29. Shao Q, Chundawat SP, Krishnan C, Bals B, Sousa Lda C, Thelen KD, Dale BE, Balan V. (2010) Enzymatic digestibility and ethanol fermentability of AFEX-treated starch-rich lignocellulosics such as corn silage and whole corn plant. Biotechnology Biofuels. 9:3-12.

30. Krishnan C, Sousa Lda C, Jin M, Chang L, Dale BE, Balan V. (2010) Alkali-based AFEX pretreatment for the conversion of sugarcane bagasse and cane leaf residues to ethanol. Biotechnology and Bioengineering. 107:441-450, 2010.

31. Gao D, Chundawat SP, Krishnan C, Balan V, Dale BE. (2010) Mixture optimization of six core glycosyl hydrolases for maximizing saccharification of ammonia fiber expansion (AFEX) pretreated corn stover. Bioresource Technology. 101:2770-2781.

32. Nagarajan DR, Krishnan C. (2010) Use of a new catabolite repression resistant promoter isolated from Bacillus subtilis KCC103 for hyper-production of recombinant enzymes. Protein Expression and Purification. 70:122-128.

33. Gobinath, R., and Chandraraj, K. (2009-Apr) Optimization of agro-residual medium for a-amylase production from a hyper-producing Bacillus subtilis KCC103 in submerged fermentation. Journal of Chemical Technology and Biotechnology, 84, 618-625

34. Gobinath, R., and Chandraraj, K. (2008-Oct) Immobilization of malto-oligosaccharide forming a-amylase from Bacillus subtilis KCC103: properties and application in starch hydrolysis. Journal of Chemical Technology and Biotechnology, 83, 1511-1517

35. Gobinath, R., and Chandraraj, K. (2008-May) Optimization of medium and process parameters for a constitutive a-amylase production from a catabolite derepressed Bacillus subtilis KCC103. Journal of Chemical Technology and Biotechnology, 83,654-61.

36. Abhipsa S. and Chandraraj, K. (2008-Jul) Comparison of in vitro Cr(VI) reduction by CFEs of chromate resistant bacteria isolated from chromate contaminated soil. Bioresource Technology, 99, 4130-4137.

37. Gobinath Rajagopalan, Chandraraj Krishnan (2008-May) a-Amylase production from catabolite derepressed Bacillus subtilis KCC103 utilizing sugarcane bagasse hydrolysate. Bioresource Technology, 99,3044-3050.

38. Elangovan, R., Ligy Philip, K. Chandraraj, (2008-Jul) Biosorption of hexavalent and trivalent chromium by palm flower (Borassus aethiopum). Chemical Engineering Journal, 141, 99-111.

39. Senthilkumar, S.R., Dempsey, M., Chandraraj, K. , Gunasekaran, P. (2008-Nov) Optimization of biobleaching of paper pulp in an expanded bed bioreactor with immobilized alkali stable xylanase by using response surface methodology. Bioresource Technology, 99, 7781-7787.

40. Elangovan, R., Ligy Philip, K. Chandraraj (2008-Mar) Biosorption of chromium species by aquatic weeds: Kinetics and mechanism studies. Journal of Hazardous Materials, 152, 100-112.

41. S. Gokulakrishnan, K. Chandraraj, Sathyanarayana N. Gummadi (2007) A preliminary study of caffeine degradation by Pseudomonas sp. GSC 1182. International Journal of Food Microbiology 113, 346-350.

42. Dillirani N, AKR Gopinath, K. Chandraraj (2006) Purification and characterization of a maltooligosaccharide-forming a-amylase from a new Bacillus subtilis KCC103. Applied Microbiology and Biotechnology, 73,591-597.

43. Elangovan R, S. Abipsha, B. Rohit, P. Ligy, K. Chandraraj (2006) Reduction of Cr(VI) by a Bacillus sp. RE. Biotechnology Letters, 28:247-252.

44. Gokulakrishnan S, K. Chandraraj, Sathyanarayana N. Gummadi (2005) Microbial and enzymatic methods for the removal of caffeine Enzyme and Microbial Technology, 37:225-232.

45. Manoj Agrawala, Pradeep S, Chandraraj K , Sathyanarayana N. Gummadi (2005) Hydrolysis of starch by amylase from Bacillus sp. KCA102: a statistical approach, Process Biochemistry, 40, 2499-2507.

46. Senthilkumar SR, Ashokkumar B, Chandra Raj K , Gunasekaran P (2005) Optimization of medium composition for alkali-stable xylanase production by Aspergillus fischeri Fxn 1 in solid-state fermentation using central composite rotary design, Bioresource Technology, 96, 1380-1386.

47. Senthilkumar SR, Ashokkumar B, Chandraraj K and Gunasekaran, P (2004) Purification and characterization of a low molecular weight endoxylanase from solid-state cultures of alkali tolerant Aspergillus fischeri, Biotechnology Letters, 26, 1283-1287.

48. Anthony T, Chandraraj K , Rajendran A, Gunasekaran P (2003) Inhibition of proteases during fermentation improved xylanase production by alkali tolerant Aspergillus fumigatus AR1. Journal of Bioscience and Bioengineering, 96, 394-396.

49. Anthony T, Chandraraj K , Rajendran A, Gunsekaran, P (2003) High molecular weight cellulase-free xylanase from alkali-tolerant Aspergillus fumigatus AR1. Enzyme and Microbial Technology, 32, 647-654.

50. Chandraraj K , Talarico LA, Ingram LO, Mupin-Furlow JA (2002) Cloning and characterization of the Zymobacter palmae pyruvate decarboxylase gene (pdc) and comparison to bacterial homologues Applied and Environmental Microbiology, 68, 2869-2876.

51. Chandraraj K , Ingram LO, Maupin-Furlow JA (2001) Pyruvate decarboxylase: a key enzyme for the oxidative metabolism of lactic acid by Acetobacter pasteurianus Archives in Microbiology, 176, 443-451.

52. Sangiliyandi G, Kannan TR, Chandraraj K , Gunasekaran, P (1999) Separation of levan-forming and sucrose hydrolysis catalyzed by levansucrase of Zymomonas mobilis using in vitro mutagenesis. Brazilian Archives of Biology and Technology, 42, 375-379.

53. Gunasekaran P, Chandraraj K (1999) Ethanol fermentation technology - Zymomonas mobilis. Current Science, 77, 56-68.

54. Sangiliyandi G, Chandraraj K , Gunasekaran, P (1999) Elevated temperature and chemical modification selectively abolishes levan forming activity of levansucrase of Zymomonas mobilis. Biotechnology Letters, 21, 179-182.

55. Chandraraj K , Chandra TS (1996) Purification and characterization of xylanase from alkali-tolerant Aspergillus fischeri Fxn1. FEMS Microbiology Letters, 145, 457-461.

56. Chandraraj K , Chandra TS (1995) A cellulase-free xylanase from alkali-tolerant Aspergillus fischeri Fxn1. Biotechnology Letters, 17, 309-314.

57. Nair BU, Kanthimathi M, Chandraraj K , Ramasami T (1994) Approaches to the aqueous chemistry of chromium(IV) and chromium(V) in macrocyclic and schiff-base complexes. Proc Indian Academy of Scinces - Chemical Sciences. 106, 681-689. Conference/Symposium Proceedings

58. Chandraraj K and Gunasekaran P (2009) Prospects of bioethanol production in India. International Conference on Food Security and Environmental Sustainability, Kharagpur, Dec 17-19. Pp.

59. Abhipsa Sarangi and Chandraraj Krishnan (2008) Effect of heavy metals on growth and Cr(VI) reduction by chromate resistant Leucobacter sp. KCH4. Proc. 14th International Conference on the Heavy Metals in the Environment, Taipei. Nov. 16-23. Pp. 236-239.

60. Babu P.S., Rai S., Arora M, Gummadi S.N., Chandraraj K. (2004) Thermotolerant biocatalysts for conversion of biomass to fuel ethanol and chemicals. Proc. 2nd International Ukrainian Conference on Biomass for Energy, Sep 20-22, Kyiv, Ukraine.

61. Chandraraj K and Chandra TS (1996) Production of cellulase-poor xylanase by a newly isolated fungus Fxn1, in Perspectives In Microbiology, Ed. R.S. Kahlon, pp.269-270.

62. Chandraraj K , Chandra TS (1994) Xylans and xylanases - Present scenario. MICON-94 & 35th Annual Meeting of Association of Microbiologists in India, 145, 457-461.

Books/Conference/Symposium Abstracts/Patents/Others

• Shereena P Joy and K Chandraraj Method for pretreatment of biomass using ammoniacal glycerol. Issued on: 10/04/2023 Patent Grant No. 428548

• N. Vignesh, K. Chandraraj, Suresh Kumar Rayala, Suriyaraj Shanmugasundaram Prema, and Selvakumar Rajendaran Method for processing waste cotton microdust into a cellulose membrane material. Issued on: 30/09/2022 Patent Grant No. 408222

• Sarangi A. and Chandraraj, K (2013) Chromate Toxicity and Bioremediation

• Abhipsa S and Chandraraj K (2009) Enzymatic reduction of hexavalent chromium in bacteria. ENVIS Newsletter, 7, 2-5.

• Chandraraj K and Gunasekaran P (2004) Bacterial Alcoholic Fermentation, in Concise Encyclopedia Of Bioresource Technology (Ed. Ashok Pandey), THRP, Inc., New York, pp.327-334.