This study is aimed at evaluating the technological characteristics of wild non-Saccharomyces sourced from banana fruit and wild honey. The isolation of yeasts was done according to standard microbiological procedures. Technological traits screened for are as follows: fermentation ability, alcohol production, flocculation ability, organic acid production, and hydrogen sulphide production. Five yeast isolates were identified as B10 (Candida tropicalis), B7 (Candida tropicalis), H4 (Candida tropicalis), H7 (Clavisporalusitaniae), and CY (Candida tropicalis), which are sugar fermenters. The percentage of alcohol produced from each sugar fermented by the yeast isolates are as follows: sucrose - B7(11.50%) > H7(8.62%) > CY (7.80%) > H4(4.88%) > B10 (4.11%); Glucose - B7(9.82%) > CY (6.28%) > B10(4.56%) > H7(4.03%) > H4(2.19%) and Fructose - H7(13.11%) > CY (9.40%) > B10(7.03%) > H4(4.41%) > B7(3.70%). Yeast isolate CY demonstrated high flocculation of 28.55 and 44.75 (%) at 5 and 15 (minutes). The organic acid produced by the yeast isolates B10, B7, CY, H4 and H7 are as follows 1.90±0.41, 3.10±0.41, 1.25±0.07, 3.90±0.41 and 2.40±0.41 (AU) respectively and Yeast isolates B7, CY, H4, and H7 produced low hydrogen sulphite concentration. Wild non-Saccharomyces could be the hope of the wine microbiologist to ease the challenges in the wine industry, as they competed flavourably with the commercial wine yeast.

This study is aimed at screening non-Saccharomyces for amino acids decarboxylation potentials. The yeasts were isolated from banana fruit and honey purchased from markets in Rivers State. The isolation and molecular identification of yeast isolates were according to standard microbiological procedures. A plate assay method for amino acid decarboxylation (biogenic amine production) screening was used. Wild Non-Saccharomyces yeast (NSY) were identified as Candida tropicalis Pe 1 (B7), Candida tropicalis WC65-1 (B10), Candida tropicalis WC57 (H4), Clavispora lusitaniae WM03 (H7), and a Commercial Wine yeast (CY) identified as Candida tropicalis zhuan4 (CY). The NSYs and CY were biogenic amine producers, from L-histidine and glutamic acid; strain variability from glycine, proline, glutamine, and asparagine decarboxylation; while L-arginine, lysine, tyrosine, cysteine, leucine, and phenylalanine were not decarboxylated at a concentration of 0.1 %. The increase in amino acid concentration influenced the number of amino acids decarboxylated - phenylalanine and leucine; L-histidine, glycine, asparagine and glutamic acid were decarboxylated by wild NSY and CY, while the strain variability of phenylalanine, proline, leucine and glutamic acid decarboxylation. The amino acids L-arginine, lysine, tyrosine, and cysteine were not decarboxylated. In terms of the concentration of amino acids, L-histidine and glutamic acid were decarboxylated and arginine, lysine, tyrosine, and cysteine were not decarboxylated by wild NSY isolates and CY. The Chi-square Test and Kendall’s Test of concordance suggest that there is no association between the amino acid concentrations (0.1 and 1 %) and biogenic amine production (P-value > 0.05). The wild NSY and CY are biogenic amine-producers, and the increase in amino acid concentration influences biogenic amine production concerning some amino acids.

Bacillus thuringiensis is a widely studied bacterium and it is known for its use in pest management. It is selectively active on pests and less likely to cause resistance; hence it is considered a suitable replacement to chemical pesticides. The study assessed the potential of Bacillus thuringiensis in controlling mosquito larvae. Bacillus thuringiensis isolates selected were tested against secondary stage larvae of mosquito. Thirty-six larvae (6 each) were transferred into each test tubes (7 x 9) cm with 30ml sterile distilled water. The stock suspension of cultures of Bacillus thuringiensis in broth was diluted to 107, 106, 10 5, 104, 103 and 102 in sterile water, following the McFarland standard method for microbial load count. The test tubes were kept at room temperature, larval mortality was observed over time within 24hrs. The results showed that all mosquito larvae died at the 107 and 106 dilutions but at dilutions 105, 104 and 103 though affecting mosquito larvae, it was highly dependent on time because there was a decrease in concentration. The study showed that B. thuringiensis is safe for use in aquatic environments, including drinking-water reservoirs, for the control of mosquito, black fly and nuisance insect larvae. The products should contain the ICPs and be free from other microorganisms and biologically active metabolites.

Studies were carried out to investigate the bioremediation potential of pig dung in a soil contaminated with spent engine oil. Soil samples were obtained from the Ofrima complex, University of Port Harcourt. The soil samples were contaminated with various concentrations (50 ml and 100 ml) of spent engine oil and allowed for 21 days for proper exposure, mimicking natural spill. This was followed by the addition of the pig dung. The experimental setup was labeled sample A (1 kg soil + 100 g pig dung + 50 ml spent engine oil) and sample B (1 kg soil + 100 g pig dung + 100 ml spent engine oil). The physicochemical parameters and the microbiological analysis were done using standard methods. The total petroleum hydrocarbon was analyzed using gas chromatographic methods. Analyses were carried out at 14 days intervals for 28 days. The physicochemical parameter results showed a reduction in pH values in the contaminated soil samples, ranging from 6.21 - 6.65 in sample A and 6.57 - 6.87 in sample B. Temperature values were constant at 230C from day 1 to day 14 in sample A and increased at day 28 to 24 0C, also for sample B, the temperature was constant at 230C from day 1 to day14 and increased at day 28 to 26 0C. The amount of heavy metal (Lead) content decreased from 4.3645 - 1.93676 (mg/kg) and 6.18361 - 3.89654 (mg/kg) for samples A and B, respectively. There was also a significant reduction in the amount of Total Petroleum Hydrocarbon, from 16631.86 - 3280.83 mg/kg for sample A and 18464.73 - 6784.60 mg/kg for sample B. The THB counts for samples A and B ranged from 7.73 - 7.91 and 7.05-8.20 (Log cfu/g), respectively. The fungal counts ranged from 3.99–4.58 and 5.12 - 7.93 (Log cfu/g) for samples A and B respectively. HUB counts ranged from 4.52–5.09 and 4.93- 5.55 (Log cfu/g) for samples A and B, respectively. The HUF counts ranged from 4.12 - 5.49 and 4.13 - 4.70 (Log cfu/g) for samples A and B, respectively. The results clearly showed that microorganisms capable of utilizing total petroleum hydrocarbon were present, also the pig dung showed both bio-stimulation and bio-augmentation tendency to attract high microbial load which supported the bioremediation of the spent engine oil contaminated soil.