Investigation on Indigenous Bacillus Isolates With Bioremediation Properties for Improving Water Quality and Shrimp Health in Malaysian Aquaculture

Indigenous marine bacteria of the genus Bacillus were selected to study their properties as potential use for bioremediation owing to their inherent versatility. Bacteria were isolated from water and sediment samples collected along the west coast of Peninsular Malaysia in brackishwater environment. Selected isolates were identified to species level using biochemical and API CH kit and three suitable isolates, Bacillus pumilus AB58, B. subtilis AB65 and B. lichenifonnis AB69 were selected for the study. Optimum growth requirements of temperature, NaCI and pH were 30°C, 1.5% and 7.5 respectively, determined for the isolates by measuring the optical density and corresponding cell number. The growth curves of the isolates were plotted and all of them reached maximum cell number during a 16-20 h incubation. The cell density in overnight cultures of B. pumilus AB58, B. subtilis AB65 and B. licheniformis AB69 were 5.7xl09 (± 0.8), 3.7xl08 (± 0.6), 5.0x109 (± 0.6) cfu/ml respectively. They had the ability to tolerate ammonia levels of up to 20 mg/l without a considerable change in cell numbers for 48 h. However, the growth was suppressed completely at 25 mg/l of ammonia. At 40 ppt salinity, all the isolates survived for 4 days without significant change in initial cell numbers (108 cfu/ml). The selected isolates were found to secrete extracellular enzymes viz., protease, gelatinase, amylase and lipase as detected by clear zone formation on substrate based agar plates. Bacillus pumilus AB58 and B. subtilis AB65 produced significantly (P < 0.05) bigger protease clear zones (19.0 ± 2.0 and 23.0 ± 4.0 diameter in mm respectively) than B. licheniformis AB69. However, B. subtiUs AB65 secreted significantly (P < 0.05) more amylase (31.0 ± 5.0 diameter in mm) than the other two isolates. All the isolates were sensitive to most of the antibiotics tested on MHA plates. These isolates were compatible with each other in mixed culture conditions. They inhibited as well as excluded all the pathogenic vibrios (Vibrio algillolyticus MIl, V. alginolyticus M12, V. parahaemolyticus MI, V. parahaemolyticus M3, V. parahaemolyticus M6, V. alginolyticus T, V. parahaemolyticus T, V. harveyi I and V. parahaemolyticus I) tested by diffusion disc, streak plate and common broth methods. Synergistic effect of isolates had significantly higher (P < 0.05) inhibition of all vibrios than the individual isolates. The isolates were confirmed for their non-pathogenicity to shrimp postlarvae (PL 29). All three isolates were tested for their effect on ammonia in simulated pond conditions. All non-aerated treatment tanks had significantly lower ammonia levels (P < 0.05) than the non-aerated control tanks, which were not treated with bacterial isolates both in case of single and combination treatments. Synergistic effect of isolates reduced the ammonia levels at a faster rate than the treatments with single isolate. Sediment properties were not significantly different between treated and control groups except for the total and available phosphorous levels, which were significantly higher in tanks treated with B. licheniformis AB69 (P < 0.05) compared to the others. The selected Bacillus isolates satisfied the criteria to qualifY them for bioremediation in aquaculture

Lichens: a novel and potential source as antimicrobials for human use

The use of lichens in medicine is based on the fact that they contain unique and varied biologically active substances, as antimicrobials.  Since they are natural antibiotics, their metabolites exert a wide variety of biological actions including antimycotic, antiviral, anti-inflammatory, analgesic, antipyretic, antiproliferative, and cytotoxic effects, they are considered as potential drugs. They contain a variety of secondary metabolites with strong antioxidant activity. These are substances which have high ability to scavenge toxic free radicals due their phenolic groups. These manifold activities of lichen metabolites have now been recognized, and therefore their therapeutic potential have great impact in pharma industries. The present article discusses the importance of lichens in inhibiting various types of human pathogens in addition to their chemical composition and pharmacological activities

Comparison of four antibiotics with indigenous marine Bacillus spp. in controlling pathogenic bacteria from shrimp and Artemia

Use of antibiotics for the control of bacterial diseases in shrimp culture has caused several adverse impacts to the industry. This has resulted in the search for alternative environment friendly approaches to overcome bacterial infections. This study was conducted to investigate the use of beneficial bacteria as an alternative to antibiotics. Ten pathogenic bacterial species isolated from shrimp, Penaeus monodon, and Artemia cysts were tested for susceptibility to indigenous marine Bacillus subtilis AB65, Bacillus pumilus AB58,Bacillus licheniformis AB69 and compared with oxytetracycline, chloramphenicol, gentamicin and bacitracin, which are common antibiotics used in Asian aquaculture. The Bacillus spp. were isolated from the local marine environment for bioremediation use in shrimp hatcheries and were proven to reduce total ammonium nitrogen. The pathogenic bacterial isolates were 90% susceptible to B. subtilis AB65, 70% susceptible to B. pumilus AB58 and B. licheniformis AB69 and 100% susceptible to oxytetracycline, chloramphenicol and gentamicin but only 40% to bacitracin. Two representative isolates of the vibrio group, Vibrio alginolyticus VaM11 and Vibrio parahaemolyticus VpM1, when tested for competitive exclusion by a common broth method using the marine Bacillus spp., showed decreased viable counts from 108 to 102 cfu mL)1.The results suggest that the action of the marine bacteria appears to be significant in protecting the host shrimp against pathogenic bacteria. In addition to the alternative use of antibiotics, the selected marine bacteria had additional bioremediation properties of reducing ammonia

Assessment of marketing strategies of tour operators towards development of tourism – a case study on Mysuru and Dakshina Kannada districts

Tourism is one of the important sectors in the economic development of the country. Many of the countries are depends mainly on income which will be generated by the tourism activities. Under the tourism concept, there are different stake holders who play a vital role. Among the stake holders of tourism, tour operators are also one of the key players towards promotion of tourism activities. The tourism sector is gaining increased importance for the economic development of countries around the world. The purpose of this paper is to give a theoretical overview of the classical and contemporary business strategies that can be implemented in a more or less modified form by tourism companies in Mysore and Dakshina Kannada districts. Paper also focuses towards how the tour operators use the marketing strategies towards development of tourism activities in Mysuru and Dakshina Kannada districts. Due to the competition among tour operators, they use different strategies for reaching out their tourism services to the tourists. Now a day, tour operators are using online marketing services to promote their tourism activities to the tourists. While providing the tourism services to the tourists, there may be the competition among recognized and un-recognized tour operators. In this aspects each and individual tour operators will implement their own strategies for the enhancement of their tourism business

Microenterprise success of home-based garment makers in Bangalore, India

Home-based producers are some of the most invisible workers in the unorganised sector in India. In many industries, including garment production, they comprise a significant proportion of the workforce. In order to document this as well as to make visible the contribution of home-based producers, proper estimates of their numbers and output are necessary. Because these producers work within their homes, often on activities closely related to household production for consumption, they are easily slipped in labour force estimates. Added to this problem is the fact that many home-based producers are women, and women have traditionally been an under-counted group within labour force statistics. The purpose of this paper is to make visible the number and contribution of male and female home-based garment producers in Bangalore, India illustrating any deficiencies in official statistics on home-based industries. The paper concludes with recommendations to incorporating the home-based producers and strategies to improve the contribution of female home-based garment producers in Bangalore

Stock market investor grievance redressal system-an empirical study

The Securities and Exchange Board of India (SEBI) laid down several regulatory measures to protect the investors of capital market. Effective investor protection is not simply a function of �law on the books�, but it depends heavily on �law in action� which depends on issues like innovative supervisory strategies, product design initiatives, capital market research, investors redress and investors education. This study is considered to be interesting for two reasons, firstly, it covers the recent trends in grievance redressal rate and secondly, it examines the fluctuations in pending grievance redressal rate. The present research is based on purely secondary data available at SEBI web sites and used analytical tools like simple percentage analysis and hypothesis testing. The paper pleads for implementation of effective investor grievance redressal mechanism