Microbiological Properties of Probioticated Kununzaki Drink Enriched with Cocoa Powder

Kununzaki- a popular and an affordable West African cereal-based beverage was enriched with cocoa powder and subjected to ‘probiotication’ with ‘probiotic’ lactic acid bacteria and subsequently investigated for sustained viability of the microbes and ability to suppress growth of food-borne bacteria. This study enumerated the different microbes in enriched kununzaki drink before and during storage, identified the isolated microbes and assessed the viability of the ‘probiotic’ lactic acid bacteria (LABs) in the drink and determined the antagonistic effect of the LABs on two selected food-borne pathogens. This was with a view to enhancing the health giving attributes of affordable kununzaki, which is already a popular beverage in Nigeria. Laboratory results revealed total viable bacteria, lactic acid bacteria and mould counts to range from 4.69 – 8.76, 6.45 – 9.74 and 6.04 – 8.77 log cfu ml-1, respectively. The microorganisms isolated were identified as: Bacillus brevis, B. Badius, B. polymyxa, B. macquariensis, B. pantothenticus, Staphylococcus aureus, S. epidermidis, Serratia marcescens, Lactobacillus delbrueckii, L. fermentum, L. plantarum, L. casei, Aspergillus niger, and Curvularia affinis. ‘Probiotic’ lactic acid bacteria were viable (69.75 log cfu ml-1) at the end of four weeks of storage. The viabilities of Lactobacillus fermentum which were 9.75 and 9.58 log cfu ml-1 at ambient and refrigerated temperatures, respectively were higher than those of other lactic acid bacteria species. The same organism was found to be active against one of the tested food-borne pathogens, Escherichia coli as evident in the diameter of zone of inhibition on plate and broth culture analyses. The study concluded that Lactobacillus fermentum could be effectively used for ‘probiotication’ of kununzaki enriched with 20% cocoa powder and the resulting product exhibited potential of checkmating a food-borne bacterial strain and by implication has the potential of promoting the health of consumers. The product was also found to be microbiologically stable for 4 weeks of storage at ambient and refrigeration temperatures.

Activity of Engineered Nano-Semiconductor Oxides against Gram Positive and Gram Negative Bacteria

Antibacterial activities of semiconductor oxides such as ZnO and TiO2 have induced research on the design of engineered nanoparticles (ENPs) for the last few decades. We had synthesized modified ZnO and TiO2 using rare earth salts and analyzed their antibacterial activities against Bacillus brevis. (Gram positive) and E. coli (Gram negative) by modified well diffusion method. Among the seventeen nanoparticles studied, Ag-TiO2 showed highest antibacterial activity against Gram positive and Gram negative bacteria. Antibacterial activities of Ni-Ag-TiO2, ZnO, Eu2O3-ZnO, DyMoO4-ZnO, GdMoO4-ZnO, DyVO4-ZnO, GdVO4-ZnO and HoVO4-ZnO were found to be significant. From the microbial plating experiments it was shown that the synthesized nano materials show a wide spectrum of antibacterial activities performed against Bacillus brevis, and E. coli. In this study we help to understand the influence of the engineered nanoparticles (ENPs) against microbes, as these ENPs finds wide applications in medicine, water treatment, in food industry as anti-coating agents.

Heterologous Expression of the Marine-Derived Quorum Quenching Enzyme MomL Can Expand the Antibacterial Spectrum of Bacillus brevis

Quorum sensing (QS) is closely associated with the production of multiple virulence factors in bacterial pathogens. N-acyl homoserine lactones (AHLs) are important QS signal molecules that modulate the virulence of gram-negative pathogenic bacteria. Enzymatic degradation of AHLs to interrupt QS, termed quorum quenching (QQ), has been considered a novel strategy for reduction of pathogenicity and prevention of bacterial disease. However, the low expression levels of QQ proteins in the original host bacteria has affected the applications of these proteins. Previously, we identified a novel marine QQ enzyme, named MomL, with high activity and promising biocontrol function. In this study, we linked the target fragment momL to pNCMO2, which provided a basis for the first heterologous expression of MomL in the antifungal and anti-gram-positive-bacteria biocontrol strain Bacillus brevis, and obtaining the recombinant strain named BbMomL. The QQ activity of BbMomL was confirmed using a series of bioassays. BbMomL could not only degrade the exogenous signal molecule C6-HSL, but also the AHL signal molecules produced by the gram-negative pathogens Pectobacterium carotovorum subsp. carotovorum (Pcc) and Pseudomonas aeruginosa PAO1. In addition, BbMomL significantly reduced the secretion of pathogenic factors and the pathogenicity of Pcc and P. aeruginosa PAO1. We tested the biocontrol function of BbMomL for prevention of plant diseases in vitro. The result indicates that BbMomL has a broad antibacterial spectrum. Compared with wild-type B. brevis, BbMomL not only inhibited fungi and gram-positive bacterial pathogens but also considerably inhibited gram-negative bacterial pathogens. Moreover, the Bacillus brevis expression system has good application prospects and is an ideal host for expression and secretion of foreign proteins.

ISOLASI, KARAKTERISASI DAN IDENTIFIKASI BAKTERI ENDOFIT KULIT BATANG SRIKAYA (ANNONA SQUAMOSA) DAN POTENSINYA SEBAGAI ANTIBAKTERI

The objective of this study was to isolate endophytic bacteria from bark of srikaya, analyzing antibacterial activity of endophytic bacteria in S. aureus, B. cereus and E. coli pathogenic bacteria, characterizing endophytic bacteria capable of inhibiting the growth of pathogenic bacteria and identification of endophytic bacteria able to inhibit the growth of pathogenic bacteria. Isolation of endophytic bacteria using TSA and NA media, bioassay on pathogen bacteria with concentration of 106 cells / ml with using Ø 6 mm wells and entering supernatant of 100 μl. Supernatant was obtained by growing endophytic bacteria in NB media shaken with shaker 150 cycles / min for 48 h at 32ᵒC then culture centrifuge at 5000 g for 30 min. Positive control using cyprofloxacin. Characterization is based on the nature of the colony, Gram paint, spore formation, and biochemical tests. The results of the study yielded 13 endophytic bacterial isolates and 4 endophytic isolates capable of inhibiting the growth of 8 pathogenic bacteria with sensitive criteria, 2 pathogenic bacteria with resistant criteria and 1 pathogen bacteria can not be inhibited its growth. Gram's paint results show that 4 endophytic isolates belong to Gram-positive, rod-shaped and spore forming cells. From the character possessed by the bacteria can be identified that the 4 bacteria endofit capable of inhibiting pathogenic bacteria are Bacillus brevis, Bacillus latesporus, Virgibacillus pantothenticus, and Bacillus circulansKeywords: Characterization, Endophytic Bacteria, Bark of Srikaya, Antibacterial

THE USE OF BIOFERTILIZERS INCREASED PLANT GROWTH WITH NO TRADE-OFF EFFECT ON GREENHOUSE GAS EMISSIONS

<p>Several experiments have been carried out to elucidate the reduction in greenhouse gas emissions as effect of replacement of chemical fertilizer by biofertilizers on alluvial soils in Indonesia. Biofertilizers “Biotara” and “Biosure” were applied along with NPK fertilizer on alluvial soil cultivated with rice. Emissions of nitrous oxide (N₂O), methane (CH₄) and carbon dioxide (CO₂) were monitored in biweekly basis up to the maximum vegetative growth of the rice plant. Oil palm empty fruit bunch (OP EFB) as well as grasses were composted with <em>Bacillus brevis</em> and <em>Bacillus megaterium </em>as activator. The composts were incorporated into alluvial soils cultivated to oil palm and the emissions of N₂O, CH₄ and CO₂ were monitored in biweekly basis. The results showed that biofertilizer “Biotara” or “Biosure” combined with NPK fertilizer (¾ recommendation dose) could increase paddy growth with no significant effect on N₂O, CH₄ and CO₂ emissions. The emissions of N₂O, CH₄ and CO₂ exhibited seasonal changes as affected by inclusion of either OP EFB and weed compost along with NPK fertilizer. Global warming potentials of each treatment for NPK, OP EFB compost and weed compost were 5.6, -5.2 and -4.9 ton CO₂equ m^-² year^-1, respectively. It could be concluded that the replacements of synthetic fertilizer with biofertilizer or compost did not have negative impact on the environment which could be promoted.</p>