Entomopathogenic nematodes (EPNs) are known to be highly pathogenic to insect pests, due to their associated symbiotic bacteria, which produce virulence factors, exo-enzymes and other harmful secondary metabolites to conquer, kill, and degrade their insect hosts. However, these properties are not fully characterized. This study reports on the antimicrobial activities of Photorhabdus sp. strain ETL, symbiotically associated to an insect pathogenic nematode, Heterorhabditis zealandica, against human pathogenic bacteria and toxigenic fungi, as well as the non-targeted profiling of its secondary metabolites (SMs) using gas chromatography coupled to high-resolution time-of-flight mass spectrometry. Fatty acids including 3-eicosene, (E)-; 5-eicosene, (E)-; eicosene; 9-octadecenamide; undecanoic acid with shown antimicrobial activities were detected. This provided more insight on the composition and bioactivities of SMs produced by the Photorhabdus sp.

Beer is an alcoholic beverage made from a cereal grain extract and is widely consumed in sub-Saharan Africa and the world at large. However, beer consumption could expose consumers to mycotoxins. In this review, we appraised the different mycotoxins associated with beer contamination, elucidating their structures and incidence in cereals involved in beer production. The common mycotoxins that are found within the brewing process are reviewed. These include aflatoxin B 1 (AFB 1 ), fumonisin (FB), ochratoxin A (OTA), zearalenone (ZEA) and deoxynivalenol (DON), which are the prime contaminants in beer produced in sub-Saharan Africa. Residual levels of <20% of AFB 1 , OTA and FB 2 together with the transformation of ZEA (into a less toxic compound β-zearalenol) can be achieved during the production of beers originating from Europe/America, while >50% of DON and higher ratios of FB 1 can be recovered in finished beer. Adsorption is the major means of mycotoxin removal during beer production. In contrast, traditional African beer processes show no significant efficient removal of mycotoxins. This is because the prevailing environmental conditions during beer production are favourable to mycotoxigenic fungal proliferation. This subsequently leads to relatively high concentration of mycotoxins in freshly processed beer, with a possible increase during the beer shelf-life owing to the absence of appropriate microbial stabilisation treatments in the finished processed beer.

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Entomopathogenic nematodes (EPNs) are among the frequently used and commercialized bio-pesticides. However, they are restricted in their infectivity, persistence, storage, and cost of production. One of the methods used to improve this is a continuous search for new isolates with significant behavioral and physiological characteristics. A novel EPN isolate, Heterorhabditis zealandica strain ETL, isolated from South Africa (GPS coordinates − 24.849721 and 28.336980) is described and studied against late-instar of Galleria mellonella (L.) and Tenebrio mollitor (L.) larvae. The morphological and molecular studies indicated this isolate as a Heterorhabditis strain. The comparison of sequences of the internal transcribed spacer (ITS) region, the 18S rRNA gene, and the D2-D3 region of the 28S rRNA gene with available sequences of other described species within the genus indicate the isolate as a new Heterorhabditis zealandica strain. The phylogenetic analysis of the sequence data places strain ETL, closest to H. zealandica strain Bartow (GU174009) in the Heterorhabditis group. This EPN was lethal to G. mellonella and T. mollitor; as infections occurred within 24-96 h. Fifty percent of the larvae population were killed within 24 h and 100% after 96 h.

Mycotoxins originate from fungal contamination of barley (and other cereals) and can be found at low levels in beer. Filtration is an effective way to remove mycotoxins. This workat a laboratory scaleassesses the effectiveness of a commercial filter aid in the removal of mycotoxins in beer. Kieselguhr (Celite 577) and rice hull ash (Pattern II type), an emerging alternative filter aid to DE, were evaluated for the removal of ochratoxin A during beer filtration. The adsorption isotherm was conducted for the filter aids adsorptive capacity against ochratoxin A (100 μg/mL). Residual ochratoxin A in beer was analysed using an immunoaffinity column and high-performance liquid chromatography. The results showed that rice hull ash (72%) was more effective in the removal of ochratoxin A in beer than Celite 577 (38%). Adsorption was the major form of ochratoxin A removal using rice hull ash, whereas with Celite 577 it was entrapment.

Entomopathogenic nematodes (EPNs) are obligate parasites to insects. They are natural enemies of numerous insects, which employ mutually related bacterial symbionts to rapidly kill their insect host. They are among the frequently used beneficial biocontrol agents of numerous insect pests in agriculture, forestry and health. These EPNs are continuing to constitute a great deal of interest for both scientists and industries. This is demonstrated from the breadth of research activities on EPNs in many countries throughout the world. More scientists are becoming trained in working with EPNs and the number of newly discovered EPN species is increasing. In South Africa (S.A.) although various studies have revealed an incredible richness of EPNs fauna with potential use as bio-control agents adapted to some soil texture and environmental conditions and underline the value of conducting more intensive surveys in natural and different parts of the country, few studies have been done in this area. This review gives an overview of the EPNs genera that include the main bio-control agents. The main species of EPNs and their symbiotic bacteria, interaction, associated effects on the insects' host, as well as their use and main insects' hosts range in S.A are described. In addition, their production technology is also discussed.