Indian Journal of Experimental Biology Vol. 51, August 2013, pp. 573-596 Review Article Actinobacteriological research in India Sonashia Velho-Pereira & Nandkumar M Kamat* Department of Botany, Goa University, Taleigao Plateau, Goa, 403 206, India Actinobacteria are important sources of compounds for drug discovery and have attracted considerable pharmaceutical, chemical, agricultural and industrial interests. Actinobacteriological research is still in its infancy in India. Early work on actinobacteria started in the 20th century and mostly focused on studying the diversity, identification and screening for antibiotics, enzymes and enzyme inhibitors. Exploration of diverse habitats for the isolation of actinobacteria, have yielded till date 23 novel species. Screening of actinobacteria for antagonistic activity, has led to the discovery of four novel antibiotics. Research on enzymes mostly covered lipases, amylases, proteases, endoglucanases, α-galactosidases, pectin lyases, xylanases, L-asparaginases, L-glutaminase and cellulases. Research on exploiting actinobacteria for other purposes such as production of enzyme inhibitors, single cell protein, bioemulsifier and biosurfactants is still in the experimental stage. This review compiles the work done in last few years, with an emphasis on actinobacterial diversity and bioprospecting for pharmaceutically important compounds like antibiotics, enzymes and other important applications. The chemical creativity and biotechnological potential of Indian actinobacterial strains are yet to be fully explored. A national strategy is required consistent with the opportunities provided by CBD-Nagoya protocol. Keywords: Actinobacteria, Antibiotics, Biodiversity, Bioprospecting, Enzymes, India Being ubiquitous in nature, actinobacteria are sources approaches are being followed8. Such approaches of bioactive compounds for pharmaceutical purposes. include, searching for the less or unexploited According to Baltz1 only a fraction of the world’s ecosystems for isolation of less studied rare biodiversity has been explored with less than one part actinobacteria expected to yield novel metabolites9 or of the Earth’s soil surface screened for potential by using modern strategies like proteomic signatures actinobacteria. The terrestrial soil has been widely with high throughput in vitro assays8, whole cell exploited for isolation of actinobacteria wherein they screening methods, sequencing of the actinobacterial perform significant biogeochemical roles contributing genomes and combinatorial biosynthesis1,7. This to the turnover of complex biopolymers2. However, review focuses on biodiversity and bioprospecting of despite scarce studies on diversity of actinobacteria actinobacteria from India, aimed at pharmaceutically from marine environment, they are proved to be important antibiotics, enzymes and other applications. potential producers of novel bioactive compounds3. In view of a rapid decline in the rate of discovery of Actinobacteria hold a prominent position as targets new genera and metabolites observed in the beginning in screening programmes due to their diversity of the 20th century and the period from 2011-2012, and account for the production of most of the being the most productive, in terms of actinobacterial discovered bioactive secondary metabolites, primarily diversity and biosprospecting (Fig. 1), actino- antibiotics2,4, immunosuppressive agents, enzymes5 bacteriological research is still in its infancy in India. and enzyme inhibitors6. With the rise in infectious However, there are still active groups making useful diseases and ~25-30,000 clinically described contributions. Top five institutions/laboratories, on the human diseases, accounting for many deaths, novel antibiotics are in demand as the prevalent antibiotics are slowly loosing their existing potencies7. Owing to the globally growing challenge of antibiotic resistant microbial strains, antibiotics drug discovery programmes have been undertaken and novel —————— *Correspondent author Telephone: +91-0832-6519349; + 91-9423889629 Fax: +91-0832-2452889 Fig. 1—Indian publications on actinobacterial diversity and E-mail: [email protected]; [email protected] bioprospecting since 1965. 574 INDIAN J EXP BIOL, AUGUST 2013 basis of interity of research efforts as evidenced by Table 1—Top five institutions engaged in publications are indicated in Table 1. actinobacteriological research Biodiversity and taxonomy Universities Research laboratories Baltz1 opined that approaches to explore random and exotic soil, could accelerate the production of VIT University CSIR-National Chemical Laboratory, Pune bioactive substances from actinobacteria. In view of Bharathidasan Research Centre, Hoechst India Limited, this, in India diverse habitats and locations (Fig. 2) University Mulund have been screened for studying actinobacterial Annamalai University CSIR-National Institute for Interdisciplinary diversity. Soil habitats (96%) have been largely Science and Technology, Trivandrum surveyed as compared to other resources like Andhra University National Bureau of Agricultural important endophytic plants (3%) and animal guts (1%). On Microorganisms, Mau the other hand, the percentage of actinobacterial isolations from marine resources (85%) is much Periyar University CSIR-Central Drug Research Institute, higher than freshwater resources (15%). Lucknow Fig. 2—Distribution of habitats sampled in India for actinobacteria. VELHO-PEREIRA & KAMAT: ACTINOBACTERIOLOGICAL RESEARCH IN INDIA 575 Research on actinobacterial diversity from genus Streptomyces being the most dominant, underexplored ecological niches of terrestrial followed by Micromonopora, Actinomadura, ecosystems from India, has led to the Rhodococcus, Microbispora, Nocardia and others isolation of 26 actinobacterial genera, with (Table 2). Table 2—Actinobacteria from terrestrial ecosystems Table 2—Actinobacteria from terrestrial ecosystems ref Species Genus Saccharopolyspora42 Soil inhabitants Saccharopolyspora sp. ♂ Genus Streptomyces 4, 10-43 Genus Streptoverticillium23 S. aurantiacus•, S. citricolor•, S. clavuligerus•, S. gulbargensis sp. Streptoverticillium sp.► nov.•, S. kavamyceticus•, S. platensis•, S. spectabilis•, Genus Thermomonospora62 ♦ ◘ Þ S. albidoflavus , S. erumpens* S. griseoruber , S. hyderabadensis Thermomonospora sp. 63 sp. nov.▲, S. hygroscopicus subsp. ossamyceticus,◊ Genus Yaniella ¢ S. manipurensis sp. nov.◙, S. sannanensis ►, S. sannanensis,♠ Y. fodinae sp. nov. •, , , , , , , , , S. tendae○, S. viridis○, Streptomyces sp. ◘ ▲ ◙ ► ♠ ◊ ■ ♂ ♀ Plant endophytes Genus Micromonospora23, 40, 43, 44 Genus Streptomyces64, 65, 66 ,ש ,S. greseofuscus ю ,ש ,S. hydroscopicus ω, ש ,Micromonospora sp. ▲,►,♣ S. aureus ю , שS. cyaneus , שS. flavus ,ש ,S. cinereus ω, ю ,ש ,Genus Actinomadura12, 41-43 S. albosporus ю , S. glaucus ω, S. lavendulaeю, ω, שS. viridis ,ש ,A. roseale•, Actinomadura sp. ◘,♂,ө S. globisporus ю ₫,∂ ,אַ ,☼ ,◄,צ ,ש ,ω , ω, ю ٭.Genus Rhodococcus45-48 S. griseorubroviolaceus ,Streptomyces sp R. kroppenstedtii sp. nov.Ψ, R. canchipurensis sp. nov. ◙, Genus Nocardia64, 66 R. imtechensisΩ, Rhodococcus sp. ◙ Nocardia sp. ω, ю, ₪,‡,й, ≈ Genus Microbispora23, 49 Genus Actinomadura66 M. indica sp. nov.♠ , M. karnatakensis sp. nov.♣ ,Microbispora sp.► Actinomadura sp. ₣,Θ, ╖ Genus Nocardia21, 40, 42 Genus Microbispora64, 66 ש ,ω, ю, צ.,Nocardia sp. ▲,○,♂ Microbispora sp Genus Kitasatospora23, 50 Genus Nocardiopsis66 Kitasatospora sampliensis sp. nov. ♠ , Kitasatospora sp► Nocardiopsis sp. б 51, 52 Genus Kocuria Genus Sacchromonospora64 ש.Kocuria himachalensis sp. nov. Ψ, Kocuria sp. ► Sacchromonospora sp 41, 42 Genus Streptosporangium Genus Saccharopolyspora66 ◘,♂ Streptosporangium sp. Saccharopolyspora sp.ч 42, 53 Genus Thermoactinomyces Genus Streptosporangium64 ►, ♂ ש ,T. thalophilus Thermoactinomyces sp. Streptosporangium sp.ω, ю 23 Genus Actinoplanes Genus Streptoverticillium64 ► ש ,Actinoplanes sp. Streptoverticillium sp.ω Genus Actinoalloteichus54 Ψ Gut A. spitiensis sp. nov. Genus Streptomyces67, 68 55, 56 Genus Agrococcus S. tritolerans ۩, S. noursei۵ ¢ sp.nov . A. carbonis sp. nov. , A. lahaulensis sp. nov. Ψ • ♦ 57 Soil inhabitants: Black soils , Surface soil of a landfill , Genus Arthrobacter ◘ ▲ ◙ § Brick-kiln soil*,Rhizospheric soil , Red soil , Desert soil, Arthrobacter sp. Limestone quarry◊, Alkaline soil►, Agricultural soil♠, Lateritic 48 Genus Brevibacterium soil ○, Bitumen (heavy crude oil) soil■, Solitary wasp and swallow Brevibacterium casei◙ bird mud nest♂,Tree Hollow♀,Forest soil♣,Termite moundsө, Genus Microbacterium58 Indian HimalayasΨ, Pesticide-contaminated soilΩ, Coal mine ♦ ¢ § M. immunditiarum sp. nov. soil ,Dairy industry effluent treatment plant , Self-heating Þ Genus Micrococcus57 compost ;ש M. lactis sp. nov. § Plant endophytes: Azadirachta indica stem ω, leavesю and roots ;◄Barleria root ;צColeus leaf≈, root ;٭Genus Norcardiopsis59 Vigna mungo nodule surface N. prasina◙ Coelogyne ovalis root☼, leafאַ, seed∂, petiole╖, stem‡; Carthranthus Genus Planomonospora23 leaf ₫; Plumbago leaf₪, stemч; Citrullus rootй; Asparagus root₣; Θ б Planomonospora sp.► Aloevera stem , leaf Genus Planococcus60 Gut: Earthworm gut (Eisenia foetida) ۩, Indian silkworm P. stackebrandtii sp. nov.Ψ breeds۵ Genus Saccharomonospora61 The novel actinobacterial species reported from India have S. saliphila sp. nov.◊ been underlined 576 INDIAN J EXP BIOL, AUGUST 2013 Isolation strategies like novel baiting bag69, 30 actinobacterial genera, with genus Streptomyces baiting