Bacterial extracellular alkaline proteases have been found to have broad spectrum industrial applications because of their stability characteristics among the bacteria. The Actinomyces are of enormous importance as they can be recovered easier than other bacteria after fermentation. Thus, the study was aimed at sourcing for potential protease producers among the Actinomycetes species and determining the cultural conditions for their optimal protease yields. Among 67% of the recovered soil isolates that demonstrated potentials for protease production on skimmed milk agar, only Norcardia sp-A2 2 , Micromonospora sp-A2 3 , Streptosporangium A-5 2 , and Streptomyces sp-A5 4 produced protease with higher activity(18.5-20.5mm) than the others (8.5-16.5mm). Preliminary protease assay in submerged shake-flask fermentation confirmed Streptomyces sp-A5 4 as the highest producer. Further studies on protease production by Streptomyces sp-A5 4 showed that maximum protease yield was achieved within 72h at 0.4% inoculum concentration. All the test organic carbon and nitrogen substrates supported protease yield (> 1.5/2.0 u/ml) but soybean and sweet potato meal gave the highest support (> 2.5/2.53 u/ml). However, their protease yields were significantly (p< 0.05) less than that of refined glucose and peptone when substituted as the carbon and nitrogen sources. The produced crude enzyme demonstrated optimal activity at pH 8.0 and temperature of 50 0 C. Therefore, the ability of Streptomyces sp-A5 4 to produce thermostable protease at a relatively low concentration indicated its potential as a good source for industrial applications.
In Nigeria, dry season garden eggs are often associated with higher fungal contamination than rain-fed garden eggs and most reports on the identified pathogens were on post-harvest crops. There is possibility that some of the implicated pathogens can be traced to the farm. Thus, the present study aimed to identify the predominant fungi contaminants of dry season pre-harvest garden egg for possible bio-control measures. Sampled pre-harvest garden eggs grouped into symptomatic and asymptomatic types were collected from three farms within January to March for two consecutive years. Standard phenotypic identification methods were adopted. The most predominant isolates were further subjected to ITS rRNA sequencing. The applied methods identified 7 common isolates across the farms in the ascending frequency of Fusarium thapsinum (6.67±10.34%) <Colletotrichum spp (11.10±17.20%)<Fusarium oxysporum (14.43±22.36%) <Fusarium solani (23.70±20.32%) <Penicillium citrinum (35.57±9.12%) <Pichia spp (52.20±7.52%)< Aspergillius niger (66.67±5.99%) which were all significant (P<0.05). Among the isolates, a higher variance of 44.5 was observed within the three farms than within their months of recovery (14.8 variance). The fresh asymptomatic garden egg had 71.4% contaminants as against 100% from symptomatic ones. Molecular assay confirmed the most predominant isolates as Aspergillus niger 41 and Pichia kudriavzeviiC101 with assigned NCBI accession numbers of ON417062 and ON417063 after their sequence deposition in Genbank. High percentage recovery of these isolates especially from asymptomatic garden eggs gave an insight of possible health problems associated with it on consumption and this calls for appropriate bio-control measures from the farm
Studies have shown that supplementation of important enzymes in poultry feed can improve the growth of birds. However, there were little or no available information on the utilization of such enzymes or the probiotic fermented culture in local feed production in Nigeria. Therefore, the aim of the study was focused on the evaluation of probiotic Lactobacillus plantarum fermented culture and its crude enzymes as chicken growth enhancers. The organism was first screened for amylase and protease producing potential using starch agar and skim milk agar respectively. Thereafter, confirmation of the produced amylase and protease enzymes via shake-flask fermentation at 30oC for 3 days was by 3,5-dinitro salicylic acid and Folin ciocalteu reagents respectively. The produced fermented culture and its recovered crude enzymes (2 %v/v) were respectively supplemented in the locally produced chicken feed for 10weeks. The chicken fed without supplement served as control and all their growths were determined every week. The screening results revealed that L. plantarum CS produced more amylase(29 mm) than protease(19 mm) with a total enzyme yield of 22.50 U/ml and 20.92 U/ml respectively, The chicken fed with supplements containing either the enzymes or the fermented culture grew faster and significantly higher (5 kg /10 wk) than those without the supplement (3.0 kg/10 wk)at p>0.05. The growth enhanced by the fermented culture ((5 kg/10 wk) was more than that stimulated by either the amylase (3.52 kg/10 wk) or the protease (3.86 kg/10 wk), although not significant. Supplementation with protease enzyme resulted in significant robust and faster growth (3.57 kg/ 7 wk) than that with amylase enzyme (3.37 kg/7 wk). These results indicated the great potentials of both L. plantarum fermented culture and its crude enzymes especially protease as chicken growth stimulants.
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