The Nelson Mandela African Institution of Science and TechnologyThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.https://dspace.nm-aist.ac.tz:4432024-03-28T18:35:58Z2024-03-28T18:35:58ZTanning capacity of Tessmannia burttii extracts: the potential eco-friendly tanning agents for the leather industryCecilia, ChinaNyandoro, StephenNyandoro, StephenJoan, MunissiMihayo, MagutaMeyer, MichaelSchroepfer, Michaelahttps://dspace.nm-aist.ac.tz/handle/20.500.12479/25102024-03-26T00:00:29Z2021-05-15T00:00:00ZTanning capacity of Tessmannia burttii extracts: the potential eco-friendly tanning agents for the leather industry
Cecilia, China; Nyandoro, Stephen; Nyandoro, Stephen; Joan, Munissi; Mihayo, Maguta; Meyer, Michael; Schroepfer, Michaela
In the present study, the tannins from stem and root barks of Tessmannia burttii Harms (Caesalpiniaceae), a plant
species abundantly growing in Tanzania and other parts of Africa, were investigated for their suitability in hides
tanning. Tannin powder was extracted at selected temperatures (30, 50 and 80 °C) and the influence of each
temperature on the crosslinking capacity was evaluated. The interaction mechanism between hide powder collagen
and the tannins was studied by Differential Scanning Calorimetry (DSC), trinitrobenzensulfonic (TNBS) acid assay and
amino acid hydrolysis methods. Extraction temperatures showed low influence on crosslinking capacity of the
tannins. However, extract obtained at 50 °C exhibited best performance in terms of gap size between T onset and
T peak. The stem bark extract yield was higher than that from the root bark, but both were within the recommended
ranges. The tannin content (61%) of T. burttii stem bark extract was above recommended value (10%), whereas its
total phenolic content and total flavonoic content were found to be above that of commercial Acacia mearnsii
tannin. The study of cross-linking parameters as a function of pH showed cross-linking to occur via a covalent
mechanism at the basic amino groups. However, the bonds were not resistant to acid hydrolysis. The observed
interaction mechanism indicated that tannins from stem and root barks of T. burttii belong to the condensed
tannin, similar to A. mearnsii (black wattle), a commercial tannin source that was used in this study as a reference.
Findings from this study depict that T. burttii extracts are auspicious eco-friendly alternative source of vegetable
tannins to overcome the use of chromium salts in the leather industry.
The research article was published in the journals of Leather Science
and Engineering 2021
2021-05-15T00:00:00ZFacile biosynthesis of Ag–ZnO nanocomposites using Launaea cornuta leaf extract and their antimicrobial activityMakauki, ElizabethMtavangu, StanslausOnita, BasuRwiza, MwemeziMachunda, Revocatushttps://dspace.nm-aist.ac.tz/handle/20.500.12479/25092024-03-26T00:00:14Z2013-11-14T00:00:00ZFacile biosynthesis of Ag–ZnO nanocomposites using Launaea cornuta leaf extract and their antimicrobial activity
Makauki, Elizabeth; Mtavangu, Stanslaus; Onita, Basu; Rwiza, Mwemezi; Machunda, Revocatus
The quest to synthesize safe, non-hazardous Ag–ZnO nanoomposites (NCs) with improved physical and chemical prop-
erties has necessitated green synthesis approaches. In this research, Launaea cornuta leaf extract was proposed for the
green synthesis of Ag–ZnO NCs, wherein the leaf extract was used as a reducing and capping agent. The antibacterial
activity of the prepared nanoomposites was investigated against Escherichia coli and Staphylococcus aureus through the
disc diffusion method. The influence of the synthesis temperature, pH, and precursor concentration on the synthesis of
the Ag–ZnO NCs and antimicrobial efficacy were investigated. The nanoparticles were characterized by ATR-FTIR, XRD,
UV–Vis, FESEM, and TEM. The FTIR results indicated the presence of secondary metabolites in Launaea cornuta which
assisted the green synthesis of the nanoparticles. The XRD results confirmed the successful synthesis of crystalline Ag–
ZnO NCs with an average particle size of 21.51 nm. The SEM and TEM images indicated the synthesized nanoparticles to
be spherical in shape. The optimum synthesis conditions for Ag–ZnO NCs were at 70 °C, pH of 7, and 8% silver. Antibac-
terial activity results show Ag–ZnO NCs to have higher microbial inhibition on E. coli than on S. aureus with the zones of
inhibition of 21 ± 1.08 and 19.67 ± 0.47 mm, respectively. Therefore, the results suggest that Launaea cornuta leaf extract
can be used for the synthesis of Ag–ZnO NCs
This research article was published in the Discover Nano 2023
2013-11-14T00:00:00ZSurvival Mechanisms and Management Challenges Associated with Silver Leaf Whitefly on Tomato in Africa: A ReviewMrosso, SeciliaNdakidemi, PatrickaMbega, Ernesthttps://dspace.nm-aist.ac.tz/handle/20.500.12479/25082024-03-26T00:00:13Z2022-04-30T00:00:00ZSurvival Mechanisms and Management Challenges Associated with Silver Leaf Whitefly on Tomato in Africa: A Review
Mrosso, Secilia; Ndakidemi, Patricka; Mbega, Ernest
Silver leaf whitefly (Bemisia tabaci Gennadius) (Hemiptera: Aleyrodidae) is a polyphagous winged insect pest that causes high yield losses in tomatoes and other vegetable crops globally. To combat the infestation by the silver leaf whitefly and other insects, tomato growers use cultural and synthetic chemical-based methods. However, the silver leaf whitefly continues to dominate the tomato production systems. Some of the reasons for such continued dominion by the silver leaf whitefly in tomato include among other reasons; little understanding of the mechanisms for survival of the insect pest by tomato production stakeholders which consequently results in difficulties in making appropriate pest management decisions, presence of diverse hosts, the ability of the silver leaf whitefly to develop resistance to synthetic pesticides and ineffective techniques used by tomato grower in combating the insect. Of these challenges, this review discusses the mechanisms for survival of the insect, current pest management options and recommendations for a way forward concerning the silver leaf whitefly management in Africa.
A research article was published by International Journal of Agriculture & Biology Volume 27, 2022
2022-04-30T00:00:00ZThe Effect of Field Margin Plants with Pesticide Properties on Growth and Yield of LablabLyatuu, EmanuelMbega, Ernesthttps://dspace.nm-aist.ac.tz/handle/20.500.12479/25072024-03-26T00:00:30Z2023-09-19T00:00:00ZThe Effect of Field Margin Plants with Pesticide Properties on Growth and Yield of Lablab
Lyatuu, Emanuel; Mbega, Ernest
Lablab crop is an essential pulse, cum vegetable, and is more adapted to different environmental conditions than
any other legume. Like other crops, it is infested by insect pests. The specific objective was to assess the effect of field
margin plants with pesticide properties on growth and yield of lablab. Lablab seeds, tephrosia vogelii powders and field
margin plants (Ocimum, Hyptis and Sphaeranthus) were used in this study. The experimental field was tilled, then the plots
of 10m x 10m were established at the distance of 20m apart and randomized complete block design (CRBD) with three
replications was used to assign treatment in each plot. The growth components plant heights (H) and the number of leaves
per plant were measured on the 4th, 8th and 12th weeks after germination while the yields was measured after harvest and
threshing. The study findings demonstrated effectiveness of field margin plants with pesticide properties at the edge in
reducing pest incidents by attracting more natural enemies on 4th week found 3 spiders and no insect pest compared to
other treatments, and reduce severity of foliage damage as well as increasing lablab yields (129.84kg/ha) compared to those
with no field margin pesticidal plants which yielded 115.49kg/ha, hence higher yields on plots with field margin pesticidal
plants in combination with application of fish bean [Tephrosia vogelii] which yielded 222.70kg/ha. Hence, the use of field
margins with desired pesticide properties offer a sustainable way to increase yield.
A research article was published by International Journal of Environmental Science Volume 8, 2023
2023-09-19T00:00:00Z