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

Two-Stage Fungal Pre-Treatment for Improved Biogas Production from Sisal Leaf Decortication Residues

Sisal leaf decortications residue (SLDR) is amongst the most abundant agro-industrial residues in Tanzania and is a good feedstock for biogas production. Pre-treatment of the residue prior to its anaerobic digestion (AD) was investigated using a two-stage pre-treatment approach with two fungal strains, CCHT-1 and Trichoderma reesei in succession in anaerobic batch bioreactors. AD of the pre-treated residue with CCTH-1 at 10% (wet weight inoculum/SLDR) inoculum concentration incubated for four days followed by incubation for eight days with 25% (wet weight inoculum/SLDR) of T. reesei gave a methane yield of 0.292 ± 0.04 m3 CH4/kg volatile solids (VS)added. On reversing the pre-treatment succession of the fungal inocula using the same parameters followed by AD, methane yield decreased by about 55%. Generally, an increment in the range of 30–101% in methane yield in comparison to the un-treated SLDR was obtained. The results confirmed the potential of CCHT-1 followed by Trichoderma reesei fungi pre-treatment prior to AD to achieve significant improvement in biogas production from SLDR

Proximate and nutrient composition of three types of indigenous edible wild mushrooms grown in Tanzania and their utilization prospects

In Tanzania wild edible mushrooms collected during the rainy season have broad cultural acceptance and constitute a traditionally very important nutritious food.  However, their assessment as food, which is based on their chemical analysis, has not been adequately studied and documented. The objective of the study was to determine the proximate nutritive potential of three indigenous edible wild  mushrooms namely Coprinus cinereus, (Schaeff) S. Gray s.lat., Pleurotus  flabellatus, (Berk and Br.) Sacc. and Volvariella volvaceae (Bull.ex.Fr) Singer, grown on composted solid sisal decortication residues. Standard procedures were used to determine the proximate chemical composition of dried samples of domesticated indigenous edible wild mushrooms. Atomic absorption spectrophotometry was used to determine the mineral element composition. The results were compared using an analysis of variance test. There were significant differences in the proximate  nutritive values of the three edible mushrooms (p>0.05). Despite differences in the chemical composition of the three indigenous edible mushroom species, the overall nutritional potential of the three mushroom species was quite good. Furthermore, the overall results indicated that the fruit bodies of the three native mushrooms studied have nutrient qualities similar to other cultivated exotic edible mushrooms, and a higher protein content than many cereals and vegetables. The results on a dry weight basis demonstrated significant amounts of protein, vitamin C and minerals, ranging from 17-28 %, 33-55 mg/100g and 5.2-3232 mg/100g, respectively. Furthermore crude fibre ranged between 6.6-11 % and carbohydrate, at 50-62 %, both of which were found to be relatively high. All three species were low in fat content, with a range of 1 to 3.3 %, and energy value (calculated), 302-313  kcal/100g. These results indicated that the studied mushrooms have good nutritive value for human beings. The fact that the domesticated mushrooms were grown  using locally adapted biotechnology increases the likelihood of their incorporation in the diet as a food item contributing protein, vitamin C and mineral nutrients. The high crude fibre and low fat content are also important from a nutritional  perspective. The researchers believe that it would be appropriate to popularise theutilization of the three mushrooms as unconventional protein rich food sources to supplement the traditional cereal Tanzanian based diet, aimed at combating the problem of protein malnutrition in Tanzania in particular and in developing counties in general.Key words: Proximate composition, Wild edible mushroom

The effect of the interaction of varying chicken manure supplement levels with three different solid sisal wastes substrates on sporocarp cap lengths and diameters, stipe lengths and diameters and dry weights of C. cinereus(Schaeff)S.Gray s.lat

The effect of the interaction of varying chicken manure supplement levels with three different solid sisal wastes substrates on sporocarp cap lengths and diameters, stipe lengths and diameters and dry weights of Coprinus cinereus (Schaeff) S. Gray s.lat Coprinus cinereus (Schaeff) S. Gray s.lat is an indigenous Tanzanian edible and medicinal mushroom, which grows in the wild on decomposed sisal wastes heaps. In the laboratory, it was cultivated on three types of sisal wastes substrates each supplemented with varying chicken manure concentrations 0, 5, 10, 15, 20 and 25% using solid-state fermentation bioreactors. The results showed that the interaction of sisal dust, sisal fibres and sisal decortications leaves wastes substrates with chicken  manure at varying concentrations, produced a highly significant effect (p < 0.05) on cap lengths and diameters, stipe lengths and diameters and dry weights of C. cinereus (Schaeff) S. Gray s.lat. The interactions of sisal dust waste with 5% chicken manure concentration induced longest mean cap length and widest mean cap diameter. On the other hand, the interaction of sisal leaves decortications wastes with 25% chicken manure  concentration produced heaviest sporocarps mean dry weight. These findings for the first time illustrate importance of chicken manure supplementation in C. cinereus (Schaeff) S. Gray s.lat cultivation on sisal decortications wastes substrates.Key words: Coprinus cinereus, chicken manure, solid sisal wastes, sporocarps, pileus, stipe

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

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

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

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

Performance of a sisal fibre fixed-bed anaerobic digester for biogas production from sisal pulp waste

A single stage anaerobic digester employing a sisal fibre waste fixed bed was studied for biogas production from sisal pulp waste. The fibre was colonized by microorganisms involved in biogas production. The sisal pulp waste to be digested was fed from the top and was sprinkled intermittently with recirculating leachate from the material. Organic loading rates of 0.1-10 kg volatile solids (VS) m-3d-1 could be applied and methane yields in the range of 0.13-0.48 m3 CH4 kg-1 VS added were obtained. The average methane content in the biogas produced from sisal pulp waste was 55%, and the biogas production rate was 0.15-0.54 m3m-3d-1. The methane yield obtained and the highest organic loading rate that could be sustained by this simple, fixed-bed digester are indications of an attractive system in terms of performance and reliability. It is concluded that the sisal fibre waste fixed bed is a promising carrier for microbes and can be employed for long-term operation without changing the bed. Tanzania Journal of Science Vol. 31 (2) 2005: pp. 41-5