Studies on the degraduation of wood sawdust by Lentinus squarrosulus (Mont.) Singer

Lentinus squarrosulus (Mont.) Singer, a basidiomycete also known as a white rot fungi, was immobilized on sodium alginate and tested for the effectiveness to degrade wood sawdust (WSD). Untreated and 0.1 M HCl-pretreated WSD samples were separately reacted in a micro-carrier bioreactor (mCBR) and the extent of degradation to form protein, glucose and ethanol was investigated. Pretreatment enhanced the production of both proteins and ethanol by average value of 72.0% over untreated WSD samples, after hydraulic retention time of 72 h. The maximum production of protein observed was 0.94 mg/ml-reaction volume and that of ethanol was 6.6 mg/ml-reaction volume, whereas glucose concentration fluctuated due to interconversion to ethanol. This report shows that L. squarrosulus (Mont.) Singer have the potentials of degrading WSD samples to important chemical compounds that are not hazardous to the environment. Key words: Lentinus squarrosulus, wood sawdust, sodium alginate, bioreactor, ethanol. African Journal of Biotechnology Vol.3(8) 2004: 395-39

Production and regulation of lignin degrading enzymes from Lentinus squarrosulus (mont.) Singer and Psathyrella atroumbonata Pegler

The influence of metal ions on the production and regulation of ligninase and mycelia extension of two type Basidiomycetes (Lentinus squarrosulus and Psathyrella atroumbonata) cultivated on lignocellulose waste was investigated. Mn2+ and Ca2+ ions stimulated growth of both fungi and mycelia extension significantly. Ligninase production increased two to twelve fold under the influence of Mn2+ and Ca2+ ions at concentrations of 20 to 80 mM. Mg2+ and K+ ions did not stimulate growth and extension of fungal mycelia, rather fungal cultures became deactivated after six days. The importance of mycelia extension and enhanced enzyme production has biotechnological applications in wood and pulp, textile and tanning, as well as in oil industries. Key words: Basidiomycetes, Lentinus squarrosulus, Psathyrella atroumbonata, ligninase, cofactors. African Journal of Biotechnology Vol.2(11) 2003: 444-44

Livestock-environment interactions: Methane emissions from ruminants

Livestock producers face a number of challenges including pressure from the public to be good environmental stewards and adopt welfare-friendly practices. However, environmental stewardship and animal welfare may have excitingly conflicting objectives. Examples include pasture-based dairy and beef cattle production where high-fiber diets increase methane emissions compared with grain feeding practices in confinement. Livestock account for 35-40% of global anthropogenic emissions of methane, via enteric fermentation and manure, which together account for about 80% of the agricultural emissions. Recent estimates indicate that the methane emissions from African cattle, goats, and sheep are likely to increase from their current level of about 7.8 million tons of methane per year in 2000 to 11.1 million tons per year by 2003, largely driven by increase in livestock numbers. This paper therefore reviews certain areas of CH4 emissions from ruminants, highlights on how some novel feed additives can decrease CH4 emissions from ruminants; and how some plants secondary metabolites might act as a selective inhibitor of methanogens. An enteric methane emission (which is one of the greenhouse gases) represents an economic loss to the farmer where feed is converted to CH4 rather than to product output. As developing countries are now responsible for almost three-quarters of such emissions, this has important implications in terms of mitigation strategies, because these countries are presently outside the remit of the Kyoto Protocol.Key words: Environment, CH4 emissions, feed additives, mitigation, ruminants

Purification and partial characterization of laccase from Lachnocladium sp.

Laccase, a multicopper oxidase that catalyzes the oxidation of various aromatics, particularly phenolic substrates, e.g. hydroquinones guaiacol, 2,6-dimethoxyphenol or phenylene diamine, was purified and partially characterised from culture filtrates of a white rot fungus, Lachnocladium sp. This enzyme was purified by anion exchange and gel filtration chromatography. Laccase activity was determined using ABTS (2, 2’-azinobis-(3-ethylbenzthiazoline)-6-sulphonic acid) substrate. The culture filtrate had maximum laccase activity of 1.62 U/ml after 14 days of incubation. The purified laccase had an optimum temperature of 50oC and its optimum pH was 6 for ABTS. The activity of this enzyme was enhanced by Fe2+, Cu2+, Zn2+ and Ca2+, and was inhibited by EDTA and sodium iodide. Laccase from Lachnocladium sp. had a Km of 0.119 mM and a Vmax of 0.313 U.Keywords: Lachnocladium sp., anion exchange chromatography, gel filtration chromatography, ABTS, DM

MYCOFLORA OF STORED PARKIA BIGLOBOSA (JACQ.) R.BR. EX G.DON (LOCUST BEAN) SEEDS FROM MARKETS IN JOS, NIGERIA AND CHANGES IN THEIR NUTRITIONAL COMPOSITION

Fungal deterioration of stored Parkiabiglobosa (locust beans) seeds was investigated in four markets in Jos North, Plateau State, Nigeria. The incidence of fungi on locust bean seeds from the different markets were as follows: Katako (90%), Angwan Rukuba (76.7%), Gada Biu (86.7%) and Farin Gada (70%) respectively for the deteriorated seeds and Katako (10%), Angwan Rukuba (23.3%), Gada Biu (13.3%) and Farin Gada (30%) for the non-deteriorated seeds. There was a significant difference (P≤0.05) in the occurrence of fungi from the different markets for both deteriorating/non-deteriorating seeds; Katako (153/25), Angwan Rukuba (99/14), Gada Biu (109/22) and Farin Gada (36/14). A total of seventeen fungal species were isolated with Aspergillus species being the most dominant. The analysis of nutritional qualities of non-deteriorated and deteriorated locust bean seeds shows that the deteriorated seeds had reduced protein (9.07%), fibre (3.62%) and carbohydrate (23.37%) contents than the non-deteriorated ones. The study demonstrates that fungi is capable of causing damage to stored Parkia biglobosa seeds and contribute to low nutritional worth of the seeds. The health implications of the effects of these spoilage fungi were discussed

Effectiveness of genomic DNA extraction protocol from three species of African Mistletoe(Lorantheceae)

Genomic DNA was isolated from the three different species of African Mistletoe parasitizing on 3 different trees. We attempted to study the expression of the â-tubulin gene in the leaves of these plant using ECO RI to target the â-tubulin gene in the genomic DNA. Results obtained revealed a fragment (2.1 Kbp) close to the documented size of the â-Tubulin gene (1.9 Kbp). The expression of the â-tubulin gene as revealed by ECO RI digestion was evident only during the wet season only, probably due to higher metabolic requirement of the parasitic plant during this season.There was very little expression of this gene fragment during the dry season