12 16 ± 0.11 15 ± 0.41 11 ± 0.21 14 ± 2.0 15 ± 0.21 SAI 22 Ac – - 11 ± 3.05 14 ± 2.22 11 ± 0.07 12 ± 1.20 SAI 20 Br – 11 ± 0.66 – 11 ± 0.02 – 13 ± 0.10 SAI 28 Br – 12 ± 2.12 – 13 ± 0.01 – 11 ± 2.07 SAI 29 Ac – 14 ± 0.31 13 ± 0.77 14 ± 0.73 – - SAI 18 Br – 12 ± 1.11 – 12 ± 1.27 – 12 ± 1.16 SAI 9 Br SB203580 – 10 ± 1.54 – - – - SAI 12 Br – 12 ± 0.97 – - – 12 ± 0.16

SAI 36 Ac – 13 ± 0.76 13 ± 0.76 14 ± 0.46 14 ± 1.17 12 ± 0.55 SAI 31 Ac – 12 ± 3.27 – 11 ± 3.09 – - SAI 32 Fg – 12 ± 0.09 11 ± 0.83 12 ± 2.39 13 ± 0.09 12 ± 1.43 SAI 35 Br – 14 ± 0.04 14 ± 0.98 14 ± 4.01 12 ± 2.17 12 ± 2.44 SAI 23 Br – - – - – 12 ± 0.26 SAI 5 Fg – - 11 ± 0.45 – - 11 ± 0.15 WEI 3 Ac – 14 ± 1.22 14 ± 0.11 15 ± 1.44 15 ± 0.11 13 ± 0.03 WEI 7 Br – 11 ± 4.11 – 12 ± 0.33 12 ± 0.43 – WEI 13 Fg – 11 ± 0.23 – 13 ± 0.76 – 11 ± 3.27 WEI 14 Ac – 14 ± 2.91 13 ± 3.23 16 ± 1.28 13 ± 4.30 13 ± 1.30 WEI 16 Br – - – 11 ± 2.99 – - WEI 19 Br – - – 10 ± 1.19 – - BS 1 Ac 13 ± 4.09 14 ± 5.10 15 ± 1.22 12 ± 0.61 13 ± 2.99 14 ± 0.91 BS 8 Br – - – - – 17 ± 2.07 BS 26 Fg – - 13 ± 0.22 15 ± 0.09 – - MAI 1 Br – 20 ± 0.11 17 ± 0.26 22 ± 1.40 20 ± 0.18 17 ± 0.99

MAI 2 Br – 24 ± 1.16 26 ± 2.33 22 ± 2.14 – 25 ± 3.17 MAI 3 Br – - 20 ± 2.19 22 ± 0.49 – - MAI 4 Ac – - – 15 ± 0.87 – - Key: Ac = Actinomycetes, Br = Bacteria, Fg = fungi, PA = P. aeruginosa, EF = E. faecalis, BT = B. thuringensis, SA = Staph aureus, BS = B. Subtilis, PV = Pr. vulgaris. SAI = Sand isolates from River Wiwi, WEI = weed isolates LDE225 from River Wiwi, MAI = marine isolates, BS = isolates from Lake Bosomtwe. Testing thermal stability of antibacterial metabolites of selected isolates About 1 ml of the broth cultures of isolates MAI1, MAI2 and MAI3 were separately inoculated into 10 ml nutrient broths and incubated at 37°C for 72 hours. They were then centrifuged at 6000 rpm for one hour to precipitate the microbial cells from the metabolite solutions. The resulting supernatants were decanted and filtered through Whatman (No. 1) filter paper into clean sterile test tubes in 1

ml quantities and exposed to various temperatures from 40 to 121°C for 15 min. They were then re-tested for antimicrobial activity against B. subtilis. The Bay 11-7085 metabolites of MAI2 showed better stability and hence was finally selected for further studies. Effect of growth factors on antibacterial activity of MAI2 metabolites Incubation period The incubation period for maximum activity of MAI2 was assessed by fermenting it in 250 ml of nutrient broth in a shaking incubator at 37°C. Aliquots of 10 ml of the culture were withdrawn at 24 h intervals and centrifuged as above.