Exploring technological strategies for valorization of solid sisal waste: A research review

The sisal industry in Tanzania generates large amounts of waste which is an un-tapped bioresource. Research was undertaken to establish appropriate technologies  for its valorisation to mushrooms, biogas and biogas manure (BGM).Physical and biological pre-treatments achieved methane yield increments of 23-30% whereas co-digestion with fish waste achieved methane yield increments of 59-94%. Sisal fibre waste was demonstrated to be a novel biofilm-carrier for treating sisal pulp leachate. With a loading rate of 9.0 kgVS/m3/day, the packed-bed bioreactor was operated without process stress. Sisal decortication waste (SLDW) and sisal boles (SBW) were found to be suitable for oyster mushroom cultivation. With water-pretreated SBW and saline-SLDW, biological efficiencies of  26-86% were obtained. SBW was utilized for commercial-scale mushroom cultivation and yielded 250kg/ton of wet substrate. Residues of mushroom cultivation (SMS) were anaerobically co-digested with cow dung manure and yielded 230-300L CH4/kg VSadded which indicated  the potential of SMS for AD.Co-digestion of SLDW with cow dung manure in a 10m3 continuous stirred tank reactor gave about 400 litres CH4/ m3/day, and 260 L/day of BGM  which was superior to NPK fertilizer. In conclusion, sisal waste has potential for valorisation, and integrating mushroom and biogas production for better economics  is feasible. Key words: sisal waste, anaerobic digestion, mushrooms, valorisatio

Utility of the Macro-Micromorphological Characteristics Used in Classifying the Species of Termitomyces

Delimitation of Termitomyces species principally rely on the macro-micromorphological characteristics of the species although recently they are supplemented by molecular techniques. Utility of these characters have never been examined to authenticate their usefulness. The present paper therefore, provides a detailed study on the efficacy of the macro and micro-morphological characters used in classifying Termitomyces species. Macromorphologically, capsize was very useful and based on it, three groups were established. Other more useful characters include colour of the cap and pseudorrhiza presence. Annulus presence, pseudorrhiza colour, size, and morphometry were apparently unuseful. Micromorphology was less informative and ambiguously used while untetra basidiospore character was revealed for the first time in this genus. In general macromorphological characteristics provide more reliable taxonomic information to delineate most of the species in the genus than micromophology. However, for the more similar species, an analysis of more stable molecular characters is required. More distinguishing characters are yet to be revealed while ascertaining the used one and taxonomic status of T. citriophylus is essential.Keywords: Characters, Macro-micromorphology, Mushrooms, Taxonomy, TermitomycesTanz. J. Sci. Vol 36 2010, 31-4

Optimization of laccase and manganese peroxidase production in submerged culture of Pleurotus sajorcaju

A white-rot fungus, Pleurotus sajor-caju, was isolated from coastal Tanzania and screened for crude lignolytic enzymes production using rhemazol brilliant blue R (RBBR) dye, 2,2-azino-bis (3- ethylbenzthiazoline)-6-sulfonate (ABTS) and guaiacol in a semi-solid medium. Laccase (Lac) and manganese peroxidase (MnP) were detected by a-napthol and pyrogallol solutions, respectively, on the guaiacol supplemented semi-solid media. The effect of temperature, pH, carbon, nitrogen, Cu2+, 2,5- xylidine, ferulic acid, Mn2+ and immobilization using Luffa cylindrica sponges in submerged culture fermentations were investigated for maximum enzymes production. After 7 days of incubation, 83 to 100% oxidation of RBBR, ABTS and guaiacol was observed. With optimized culture conditions, the fungal filtrate had maximum Lac and MnP activities of 80 and 0.94 U/ml, respectively compared to 0.62 and 0.0003 U/ml obtained with non-optimized ones; amounting to 129 and 3133 times increase in Lac and MnP activities, respectively. The improved crude enzymes activities, RBBR decolourization, ABTS and guaiacol oxidation capabilities of P. sajor-caju show its potential as a source of industrial enzymes for biotechnological applications.Key words: White-rot fungi, optimization, Pleurotus sajor-caju, laccase, manganese peroxidase, submerged fermentation, immobilization

Optimized Production of Lignin Peroxidase, Manganese Peroxidase and Laccase in Submerged Cultures of Trametes Trogii Using Various Growth Media Compositions

A white-rot fungus, Trametes trogii, was isolated from coastal Tanzania and screened for crude lignolytic enzymes production using Rhemazol Brilliant blue R (RBBR) dye, 2,2-azino-bis (3-ethylbenzthiazoline)-6-sulfonate (ABTS) and guaiacol in a semi-solid medium. Lignin peroxidase (LiP), manganese peroxidase (MnP) and Laccase (Lac) were detected by pyrogallol and !- napthol solutions, respectively on the guaiacol supplemented solid media. The effect of temperature, pH, carbon, nitrogen, Cu2+, 2,5-xylidine, ferulic acid, varatryl alcohol and Mn2+ in submerged culture fermentations were investigated for maximum enzymes production. After 7 days of incubation, 72-100% oxidation of RBBR, ABTS and guaiacol was observed. With optimized culture conditions, the fungal filtrate had maximum LiP, MnP and Lac activities of 0.18, 4.44 and 593 U/ml, respectively compared to 0.0011, 0.0054 and 2.3 U/ml obtained with non-optimized ones, amounting to 16,264%, 82,122% and 25,683% increase in LiP, MnP and Lac activities, respectively. The enhanced crude enzymes activities, RBBR decolorization and ABTS guaiacol oxidation capabilities of T. trogii show its potential as a source of industrial enzymes for biotechnological applications.Keywords: Optimization, Trametes trogii, lignin peroxidase, manganese peroxidase, laccase, fermentation, submergedTanz. J. Sci. Vol 36, 2010, 1-1

Prevalence and risk factors for vaginal candidiasis among women seeking primary care for genital infections in Dar es Salaam, Tanzania

Objective: To determine the prevalence and risk factors for vaginal candidiasis (VC) among women seeking primary care for genital infections. Design: Cross-sectional study. Setting: Ilala Municipal Hospital in Dar es Salaam, Tanzania. Subjects: Four hundred and sixty four women presenting with complaints of genital infections. Results: Of the 464 women examined, 177 (38.1%) had abnormal vaginal discharge, 68(14.7%) had genital ulcers, 272 (58.6%) had genital pruritis, 18 (3.9%) had genital warts and 58 (12.5%) had chancre. The prevalencies of VC, bacterial vaginosis, HIV, T vaginalis, N. gonorrhoeae and syphilis were 45%, 48.4%, 22%, 93%, 1.5% and 4.3%, respectively. The occurrence of VC was positively associated with HIV, (OR=1.81, 95% CI (1.0-2.67), bacterial vaginosis; (OR=2.6, 95%CI (1.7-3.9), genital pruritis; (OR=1.8 1, 95%CI (1.2- 2.7) genital discharge; (OR=1.867, 95% (1.28-2.73) and negatively with T. vaginalis (OR=0.27, 95% CI (0.12 - 0.6), occupation (OR=0.65, 95%CI (0.35-0.86)) and with education (OR=0.43, 95% CI (0.11-0.73). There were increased but non-significant odds for VC in patients with syphilis (OR=1.6 95%CI (0.6-4.3) and venereal warts (OR=2.5 95% CI (0.92-6.8) VC was not associated with N. gonorrhoeae, genital ulcers, age at first intercourse, number of sexual partners, marital status or antibiotic usage. Conculsion: The high prevalence of vaginal candidiasis among women with genital infections should be taken into account when updating policies concerning syndromic management of sexually transmitted diseases. More gender specific approach to syndromic management of sexually transmitted infections in females should be considered. East African Medical Journal Vol.82(3) 2005: 139-14

Enabling visually impaired people to use touch screen phones

Includes bibliographical referencesMost mobile applications are not designed for visually impaired people. The concept of universal design is not adopted by most application developers. Therefore, interaction between a visually impaired user and the mobile application becomes cumbersome. Assistive technologies such as screen readers have been developed for different mobile device manufacturer s for visually impaired users. However, they only support the most popular languages spoken in the world such as English. To our knowledge, although research on assistive technologies for the use of mobile devices by visually impaired people has been done, information on that relating to minority languages such as Swahili is virtually non-existent. Therefore, this study investigated the challenges faced by visually impaired Swahili speakers when using mobile phones and then developed a mobile phone application which would enable them to use touch screen phones more independently. As a user center design methodology was adopted, visually impaired people were the focal point for this study. The mobile application was designed and implemented based on the feedback from the participants in all iteration phases and thereafter the final evaluation of a complete application was conducted. The results of the user evaluation showed that most of the visually impaired users were able to complete the tasks independently and were excited to practice even more. Although, the results showed that the sliding - text entry method had more problems than the Braille - method, still users showed preference for the former method. Furthermore, with regard to spoken feedback, the users were willing to use the app even though the quality of the voice was not natural. Overall, the mobile application developed was found to be usable and preferable. While the challenges were explored on the common basic features, it is believed that this work has laid a solid platform for future extensions

Web-based corpus acquisition for Swahili language modelling

Finding large amounts of text data for use in natural language technology is difficult for under-resourced languages such as Swahili. The corpora that are readily accessible for these languages are not sufficient to be used in language technologies, whose requirements can run into the hundreds of millions of words. This paper describes how we can take advantage of search engines such as Google together with crawling tools to collect Swahili text from the Web. We also share the experience of cleaning up and normalising the resulting text data. Finally, we show some preliminary results of the evaluation of the language models built from our corpus as well as results of how they compare to those built from the Helsinki Corpus

Identification of Tanzanian saprophytic edible mushrooms by amplification and sequencing of ITS/LSU regions of ribosomal RNA operon

In this study, ten wild saprophytic edible mushrooms samples, collected from Tanzania natural forests and planted trees, and their two domesticated forms were characterized by in-vitro/in-vivo amplification and sequencing of ITS/LSU regions. Mushroom genomic DNA was extracted by ZR Fungal/Bacterial DNA MniPrep Kit. ITS and LSU regions were amplified using ITS-4/ITS-5 and LR16/LROR primers, respectively and sequenced. The amplicons with messy sequences were cloned. For analyzing recombinant E. coli DH5α cells, colony PCR and sequencing were done using M13-F/M13-R primers. The studied mushrooms were identified as Amylosporus sp. IJ-2014, Polyporales sp., Polyporus tenuiculus, Pleurotus cystidiosus, Laetiporus sp. IJ-2014, Lentinus sajor-caju, Favolus roseus and Auricularia polytricha. The ITS-based phylogeny inferred by Neighbor-Joining method accommodated six genera under bootstrap support values of 100% with each genus consisting mushrooms of a single species. The LSU-based phylogeny inferred by Maximum Likelihood method accommodated nine genera with bootstrap support of ≥ 66% with some genera consisting mushrooms of different species. From these results, it is clear that both ITS and LSU markers successfully discriminated wild saprophytic edible mushrooms to their respective genera but ITS marker demonstrated the higher resolving power at the species level than LSU marker.Keywords:  Saprophytic edible mushrooms, ITS, LSU, RNA opero

Nile perch fish processing waste along Lake Victoria in East Africa: Auditing and characterization

Worldwide, fish industry wastes are an important contaminant having an impact on the environment. The recovery of value added products from these residues constitutes an important waste reduction strategy for the industry. In East Africa, Nile perch fish processing into chilled fish fillet for export along Lake Victoria generate large proportions of both solid and liquid wastes. However, no thorough auditing and characterization of the waste has been done that would guide potential value addition through bioconversions and waste management. Auditing by surveying and mapping the fish processing industries was conducted along the lake. Waste quantification was done using specific guidelines for assessment of fish wastes. Analysis of the waste was carried out using standard methods. Annual solid waste and wastewater generation was estimated at 36,000 tonnes and 1,838,000 m3, respectively. The wastewater generated was high strength with a total chemical oxygen demand of 12,400 mg/l and solid content of 5,580 mg/l. The wastewater contained 6,160 mg/l of lipids and 2,000 mg/l of protein. The Nutrient content was 20 mg/l of total phosphorous, 340 mg/l organic nitrogen and 61 mg/l of ammonia nitrogen. The current fish waste management systems in place were found to be neither efficient nor profitable, thus profitable options of fish waste utilization and waste reduction strategies are imperative. Modern and economically viable options of fish waste value addition, decision scheme and waste reduction strategies have been highlighted in this paper. In conclusion, large amounts of fish waste generated are a rich source of lipids and proteins, which could be utilized for production of value added products through bioconversions.Key words: Nile perch, fish waste, auditing, characterization, value addition, utilization