Department of Molecular Biology and Biotechnology

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Biogas Technology Research in Selected Sub-Saharan African Countries–A review
(2009) Mshandete, Anthony M.; Parawira, Wilson
This reviews aims to provide an insight and update of the state of biogas technology research in some selected sub-Saharan African countries in peer reviewed literature. This paper also aims to highlight the sub-Saharan countries’ strengths and weaknesses in biogas research and development capacity. An attempt is made to pinpoint future research in critically reviewing the biogas technology research. The methane-producing potential of various agriculturally sourced feedstocks has been researched, as has the advantages of co-digestion to improve carbon-to-nitrogen ratios and the use of pretreatment to improve the hydrolysis rates. Some optimisation techniques associated with anaerobic digestion including basic design considerations of single or two-stage systems, pretreatment, co-digestion, environmental conditions within the reactor such as temperature, pH, buffering capacity have been attempted in some of the researches in Nigeria, Tanzania, and Zimbabwe. However, there appears to be little research in biogas technology in many sub-Saharan African countries in internationally peer reviewed literature. Biogas production from large quantities of agricultural residues, animal wastes, municipal and industrial wastes (water) appears to have potential as an alternative renewable energy for many African countries if relevant and appropriate research is carried out to adopt the biogas technology to the local conditions in African countries. African scientists are urged to carry out research in biogas technology to locally demonstrate the feasibility, application, and adaptation of this technology and help improve the quality of energy supply in their respective countries.
Combined Production of Bioethanol and Biogas from Peels of Wild Cassava Manihot Glaziovii
(Elsevier, 2015) Moshi, Anselm P.; Temu, Stella G.; Ngesa, Ivo A.; Malmo, Gashaw; Hosea, Ken M.; Elisante, Emrode; Mattiasson, Bo
Cassava peels were pre-treated with alkali, enzyme and in sequential combination of alkali and enzyme, and used for production of bioethanol or biogas, or both (in sequence, bioethanol followed by biogas). The Biogas Endeavour and Automatic Methane Potential Test Systems were used for production of bioethanol and biogas, respectively. The bioethanol yield and volumetric productivity achieved with alkali pre-treatment combined in sequence with enzyme pre-treatment were 1.9 mol/mol and 1.3 g/L/h which was higher than the yield (1.6 mol/mol) and volumetric productivity (0.5 g/L/h) obtained from only enzyme pre-treated peels. Alkali combined in sequence with enzyme was proven to be the best treatment showing a 56% improvement in methane yield compared to the yield from untreated sample. Combined ethanol and methane production resulted in 1.2–1.3-fold fuel energy yield compared to only methane and 3–4-fold compared to only ethanol production. This study therefore provides practical data on the scenario best suited for the harnessing of energy from cassava peels.
Effect of Aerobic Pre-Treatment on Production of Hydrolases and Volatile Fatty Acids during Anaerobic Digestion of Solid Sisal Leaf Decortications Residues
(2008) Mshandete, Anthony M.; Björnsson, Lovisa; Kivaisi, Amelia K.; Rubindamayugi, Mugassa S. T.; Mattiasson, Bo
The effect of aerobic pretreatment on the production of hydrolases and volatile fatty acids during anaerobic digestion of solid sisal decortications leaf residue (SLDR) was investigated. Batch solid waste bioreactors with working volume of 2 litres were used in this study. Batch loads of aerobically treated or untreated sisal leaf residue inoculated with activated sludge mixed culture were packed into the bioreactors and operated anaerobically for 400 h. The fermentation products were mainly (mg/g total volatile fatty acids, VFAs): acetic acid (287), n-butyric acid (201), n-valeric acid (96) and caproic acid (62) as well as with low amounts of propionic acid and iso-butyric acid for aerobic pre-treated sisal leaf waste solids. Contrarily, for the untreated system, the fermentation products were chiefly (mg/g total volatile fatty acids): propionic acid (317), iso-butyric acid (276), n-butyric acid (96), acetic acid (84) and insignificant amounts of n-valeric acid, iso-valeric acid and caproic acid. Although the activities of hydrolytic enzymes found were similar for both treated and untreated SLDR, proportions of VFAs obtained with the former residues appeared to be better substrates for biomethanantion than those obtained from the latter substrates. These results indicated the potential of aerobic pre-treatment for enhanced bioconversion of SLDR. The present study, reports for the first time the types and levels of VFAs and hydrolases produced during anaerobic digestion of aerobic pre-treated SLDR and could be used as a basis for designing a pilot scale process.
Enhancement of Anaerobic Digestion of Nile Perch Fish Processing Wastewater
(2009) Gumisiriza, Robert; Mshandete, Anthony M.; Rubindamayugi, Mugassa; Kansiime, Frank; Kivaisi, Amelia K.
In East Africa, Nile perch processing into fish fillets for export generates large proportions of both solid and liquid fish wastes. These wastes are improperly utilized and/or disposed off untreated leading to environmental pollution problems. On the other hand, Nile perch fish processing wastewater (FPW) contains high concentrations of lipids and proteins, which have high methane yield potential. However, anaerobic digestion (AD) of FPW for methane production is limited due to process inhibition by lipids and ammonia intoxication. To overcome these limitations, the effects of co-digestion, physical and biological pretreatments on extent of methane yield were investigated. At a loading ratio of 1:1 (inoculum to substrate) with raw FPW, a methane yield of 0.56 m 3 /kgVS was obtained. Co-digestion of the residue with 10% gVS of brewery wastewater enhanced methane yield to a highest increment of 66%. Long chain fatty acids (LCFA) removal prior AD enhanced methane yield to an increment of 52% at LCFA removal of 8%. Pretreatment of FPW with aerobic microbial cultures isolated from a fish waste stabilization pond enhanced methane yield to an increment of 60% after 18 h, 68% after 15 h and 76.0% after 12 h of incubation, respectively, for strains CBR 11, BR 10 and a mixture of the two (CBR 11 + BR 10). The present study reports for the first time improvement of AD of Nile perch FPW by co-digestion, physical and biological pre-treatment methods and could be used as a basis for designing a pilot scale process.
Enhancement of Anaerobic Digestion of Sisal Leaf Decortication Residues by Biological Pre-Treatment
(Asian Research Publishing Network, 2009) Mutemi, Muthangya; Mshandete, Anthony M.; Kivaisi, Amelia K.
In recent years, the use of agro-industrial residues as feedstocks for biogas production has gained great attention worldwide due to limited reserves of fossil fuels. The sisal industry in Tanzania generates large quantities of sisal leaf decortication residues (SLDR) with good potential for biomethane production. However, the process is limited by the lignocellulosic nature of SLDR, making it not effectively degraded under anaerobic conditions. The effects of biological pretreatment of SLDR under solid state fermentation with a ligninolytic CCHT-1 strain and Trichoderma reseei at different inoculation rates and incubation periods to improve methane production were investigated. The methane production potential of the pretreated substrate was determined in batch anaerobic bioreactors. SLDR was pre-treated with CCHT-1 for 4 days at an inoculation rate of 10 % (wet weight inoculant/ SLDR) gave methane yield of 0.203±0.019 m3 CH4/kg VSadded, while pre-treatment of SLDR with T. reseei for 8 days at an inoculation rate of 25 % (wet weight inoculant/SLDR) gave methane yield of 0.192±0.024 m3 CH4/kg VSadded.This was an increment of between 24 to 30% in methane yield, compared to 0.145±0.015 m3 CH4/kg VSadded obtained for the untreated samples. In conclusion, the results demonstrated the suitability of biological pre-treatment method using fungi for enhanced anaerobic digestion of SLDR.
Mixed Palm Oil Waste Utilization through Integrated Mushroom and Biogas Production
(2016) Temu, Stella; Moshi, Anselm P.; Nges, Ivo A.; Mshandete, Anthony M.; Kivaisi, Amelia K.; Mattiasson, Bo
Aim of the Study: The study was to integrate mushroom and biogas production using mixed palm oil to provide both food and energy source to palm oil producing communities as well as reducing environmental pollution. Design of the Study: Mixed palm oil waste was divided into two portions. One portion was used for mushroom cultivation and afterwards the spent mushroom substrate and the untreated portion were used for biogas production. Methodology: Structural sugars analysis was performed using double acid hydrolysis technique. Total crude protein was determined through kjeldal acid digestion method. Lipids were extracted using a mixture of chloroform and methanol and quantified gravimetrically. The mushroom strain (Coprinus scinereus) was cultivated on the mixed palm oil waste. Afterwards, the spent mushroom substrate and the untreated palm oil waste were subjected to anaerobic digestion in automatic methane potential test system. Place and Duration of Study: The study was completed in 2 years from 2014-2015. Mushroom cultivation was carried out at the University of Dar-e salaam, Tanzania, whereas feedstock characterization and anaerobic digestion were performed at Lund University, Sweden. Results: Compositional analysis disclosed that the feedstock contains (% w/w) 0.1 proteins, 3.3 carbohydrates, 22.5 lipids, and 73 lignin. Mushroom yield was 0.64 g /g of substrate at a biological efficiency of 71.4 g/100 g of substrate and productivity of 21.5±0.5%. Consequently total carbohydrates and lipids were decreased by 70% and 76% while the relative content of lignin and protein increased by 23% and 50%, respectively. Particle size reduction (<4 mm) resulted to increased methane yield by 66%. The untreated and biologically treated mixed palm oil wastes yielded 517 and 287 of CH4 L/Kg VS added which corresponded to 80% and 64.5% of theoretical methane yield, respectively. Conclusion: Combined mushroom and biogas production offer superior benefits in the utilization of the palm oil waste.
Nile Perch Fish Scales a Novel Biofilm Carrier in the Anaerobic Digestion of Biological Pre-Treated Nile Perch Fish Solid Waste
(2013) Kassuwi, Shaaban A. A.; Mshandete, Anthony M.; Kivaisi, Amelia K.
Improved stability and anaerobic digestion (AD) process in a packed bed bioreactor can be achieved if bacterial consortia are retained in the process through the use of biofilms carriers. Three methanogenic biofilms carriers for biomass retention were studied to evaluate the performance of methanogenesis AD of Nile Perch fish solid wastes pre-treated by bacterial culture coded (CBR-11). The carrier material evaluated consisted of sisal fibre waste, pumice stones and Nile perch fish scales. Process performance was investigated by increasing the organic loading rate (OLR) step-wise. The best results were obtained from the bioreactor packed with Nile perch fish scales. It had the lowest total volatile fat acids (TVFA) accumulated at OLR in the range of 1-12 g volatile solids (VS)/l/d. The degradation pattern showed that the TVFAs was limiting at higher OLRs. The pH profiles showed an increasing pattern with an increase in OLRs. The pH was low (8-8.3) at low OLRs (1-6) gVS/l/d and increased to a higher level (8.3-8.7) at higher OLR (9-12) gVS/l/d. Despite the high pH level reached, the bioreactor packed with fish scales had a good ability to withstand the changes in load and VFA concentrations shocks that can occur in packed bed anaerobic bioreactors. In conclusion Nile perch fish scales was demonstrated to be potential novel biofilms carrier that would work well in methanogenic biofilms bioreactors treating fish solid waste. Moreover, Nile perch solid fish wastes and fish scales are available within the vicinity, which could make AD scale-up at fish processing industry feasible and cost effective
Two-Stage Anaerobic Digestion of Aerobic Pre-Treated Sisal Leaf Decortications Residues: Hydrolases Activities and Biogas Production Profile
(2008) Mshandete, Amelia K.; Björnsson, Lovisa; Kivaisi, Amelia K.; Rubindamayugi, Mugassa S. T.; Mattiasson, Bo
A two-stage system was investigated for anaerobic digestion (AD) of aerobically pre-treated sisal leaf decortication residue (SLDR) with regard to hydrolytic enzymes and biogas production. The system consisted of a solid-bed bioreactor for hydrolysis connected to methanogenic bioreactor packed with sisal fibre decortication residues (SFDR) as biofilm carriers. Some of the enzymes produced by microorganisms to hydrolyse SLDR were found to be pectinase, filter paper cellulase, amylase, - glucosidase, carboxylmethyl cellulase, xylanase and protease. Enzyme activities observed in the acidogenic bioreactor were much higher than those in the methanogenic bioreactor. The hydrolysis and the methanogenic stages were well separated, as indicated by the high carbon dioxide production, high volatile fatty acids (VFAs) concentration and low pH in the acidogenic bioreactor compared with high methane production, low VFAs concentration and above neutral pH in the effluent of the methanogenic bioreactor. Digestion of SLDR gave energy yields of 2.45 kWh/kg volatile solids added in the form of methane. The integrity of the methane filter was maintained throughout the period of operation producing biogas with 51 - 70% methane content. A stable effluent pH showed that the methanogenic bioreactor had good ability to withstand the variations in load and VFAs concentrations that occurred in the two-stage process. In conclusion, the results of this study showed that the two-stage system was suitable for effective stabilization and biomethanation of SLDR.
Two-Stage Fungal Pre-Treatment for Improved Biogas Production from Sisal Leaf Decortication Residues
(2009) Mutemi, Muthangya; Mshandete, Anthony M.; Kivaisi, Amelia K.
Sisal leaf decortications residue (SLDR) is amongst the most abundant agroindustrial residues in Tanzania and is a good feedstock for biogas production. Pretreatment of the residue prior to its anaerobic digestion (AD) was investigated using a twostage 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.

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