Analysis of the optimum pH and salinity conditions for the cultivation and biomass production of Chlorella vulgaris from cassava waste

Biofuel serves as an alternative energy to the common fossil fuels currently in use globally and are drawing increasing attention worldwide as substitutes for petroleum-derived transportation fuels to help address challenges associated with petroleum derived fuels. Third generation biofuels, also termed advanced biofuels, are produced from fast growing microalgae and are potential replacements for conventional fuels. The growth and biomass production of these microalgae is dependent on the conditions they are cultivated such as pH and Salinity. Cassava waste mixtures were cultivated on Chlorella vulgaris stock culture at different concentration ratio at ambient temperature, natural light and dark conditions at 670nm absorbance for 14 days. Optimum growth was obtained at 160:40 for cassava peel water to cassava waste water CP:CW. pH variations 6.0, 6.5, 7.0, 7.5, 8.0, 8.5 and 9.0 were checked to determine the optimum pH for the growth and biomass production of Chlorella vulgaris on the optimum cassava waste mixture concentration. It revealed that at pH 6.5, optimal growth and biomass production was achieved, minimal growth was observed at pH 8.0 while minimal biomass was produced at pH 9.0. Salinity variations of 5, 10, 15, 20, 25, 30, 35 and 40 mg/l were used to determine the growth response and biomass production of Chlorella vulgaris. It revealed that salinity variation at 10ppm will be necessary for highest growth on the cassava waste as well as in biomass production. The use of optimal pH and salinity can significantly increase biomass production thus enhancing biofuel production.

Molecular identification and technological properties of yeasts isolated from spontaneously fermented cassava waste pulp

The aim of this work was to report on molecular identification and technological properties of the yeast flora isolated from spontaneously fermented cassava waste pulp. This was done with a view of obtaining yeast strains that could be used as a starter culture for the fermentation of cassava waste pulp. Molecular identification was based on the nucleotide sequence of the ITS region of the genomic DNA of the yeast isolates while the technological properties evaluated include linamarase (U/mL), gelatinase, and haemolytic activity; growth at pH 2.5 and tolerance to 2 % bile salt. All the representative five isolated yeasts were identified as Geotrichum silvicola KLP04 – KLP08. The isolates exhibited linamarase activity ranging between 3.3 and 4.2 with strain KLP04 having the highest value and strain KLP05 the least. None of the isolates demonstrated gelatinase and haemolytic activity except strain KLP08 which was partially haemolytic. All the examined yeasts exhibited good growth at pH 2.5, with strain KLP08 having the highest viable counts of 4.1 log10cfu/ml and strain KLP04 the least value of 3.5 log10cfu/ml after 72 h of growth. All the identified yeasts showed strain-specific tolerance to 2% bile salt with strain KLP04 having the highest viable count of 4.3 log10cfu/ml and strain KLP08 the least value of 2.2 log10cfu/ml at the end of 72 h of incubation. Based on all the examined technological properties, Candida silvicola KLP04 strain had the highest potential to be considered for starter culture for the fermentation of cassava waste pulp.

SYNTHESIS L-LACTIC ACID FROM FERMENTATION OF CASSAVA PULP BY USING TEMPEH INOCULUM

SYNTHESIS L-LACTIC ACID FROM FERMENTATION OF CASSAVA PULP BY USING TEMPEH INOCULUM. This study used cassava waste pulp as a fermentation substrate to produce lactic acid using a tempeh inoculum. Tempeh inoculum is a mixed culture of Rhizopus with Rhizopus oligosporus as the primary fungus. Lactic acid is an organic acid most widely used in the food, pharmaceutical, cosmetic and chemical industries. One of the important uses of lactic acid is as a raw material for producing Polylactic Acid (PLA) biopolymers, namely polymers that can decompose naturally in a relatively fast time. The analysis was performed using the Response Surface Methodology (RSM) method and the Box Behnken Design (BBD) experimental design with substrate concentration parameters, inoculum concentration, and incubation time on lactic acid. The fermentation process is carried out using a flask shaker at a temperature of 30 ºC, pH 6.0, and a rotational speed of 150 rpm. The optimum yield for lactic acid is 6.65 g/L. It was acquired at substrate 20 g/L, inoculum concentration 0.30 % (w/v) at an incubation time of 72 hours.

Detoxification and nutritional enrichment of cassava waste pulp using Rhizopus oligosporus and Aspergillus niger

The present study evaluated the detoxification and nutritional enrichment potentials of the fermented cassava waste pulp obtained through different processing methods of sweet (S) and bitter (B) cassava varieties by fermentation with Rhizopus oligosporus and Aspergillus niger. Four batches [two with both bark and cortex of the tuber removed (S- and B-), two with bark only removed (S+ and B+)] of cassava waste pulp (CWP) were produced from each of S and B varieties. CWP from the four treatments were then subjected to Rhizopus oligosporus, Aspergillus niger, and natural fermentation. Cyanide (mg HCN/kg), phytate (mg/100g), tannin (mg/100g), pH, crude protein (N X6.25) (%), ash (%), Fe, P, K and Ca (mg/100g) content of the unfermented and fermented CWP were determined using standard procedures. The range of the reduction (%) in cyanide content for Rhizopus oligosporus fermented CWP (RCWP), Aspergillus niger fermented CWP (ACWP), and naturally fermented CWP (NCWP) were 86.24 – 91.95, 79.68 – 84.34 and 72.96 – 78.58 while those for phytate were 58.82 – 71.20, 29.98 – 39.26 and 36.16 – 40.32 respectively. Fermentation had no significant (p>0.05) effect on the tannin content while the pH range of NCWP, RCWP and ACWP were 7.20 – 7.50, 5.41 – 6.40, and 3.83 – 4.21, respectively. The range of the increase (%) in the protein content for NCWP, RCWP, and ACWP was 346 – 375 , 671 – 728 and 508 – 542 while those of the ash content were 7.16 – 7.91, 6.72 – 6.84, and 5.42 – 5.63 respectively. Of all the examined minerals, only calcium increased by 5.68 – 26.89, 49.96 - 70.43, and 59.71 – 98.87 % in NCWP, RCWP, and ACWP respectively. Results from the present study are indicating that controlled fermentation offers greater benefit over natural fermentation and that the cassava variety and not the peeling method will determine the extent of detoxification and nutrient enrichment.

Isolation and optimization of the fermentation condition of cellulolytic microbial isolates from cassava waste water

The study was conducted to isolate and identify cellulose producing microorganisms from cassava waste water. Cassava waste water sample was obtained from a cassava processing factory at Lokogoma town in Wushishi Local government area of Niger State. The microorganisms were isolated, identified and counted by standard microbiological methods. The mean bacteria count ranges from 6.8 x 103 cfu/mL-1 to 2.1 x 103 cfu/mL-1 while the fungi count ranges from 3.2 x 103 cfu/mL-1 to 1.2 x 103 cfu/mL-1. A total of eight (8) bacterial; Staphylococcus aureus, Bacillus anthrax, Bacillus subtilis, Escherichia coli, Klebsilla sp, Bacillus megaterus, Staph. Epidermidis and Pseudomonas aeruginosa, and six (6) fungi; Saccharomyce serivicea, Aspergillus niger, Penecillium sp., Muccor sp., Aspergilus flavus and Aspergilus fumigetus isolates were identified in the waste water. Among these organism, the best cellulase activity was recorded for Bacillus subtilis (10.39 x 10-4 mg/ml/sec) and Aspergillus niger (11.21 x 10-4 mg/ml/sec). However, maximum activity was obtained at pH ranges from 3 ~ 9, temperature ranges from 30 oC ~ 80oC and substrate concentrations ranges from 1.5% ~3.0%. In conclusion, cassava processing water regarded as waste water could be an alternative source of microorganisms capable of producing cellulase enzyme for industrial purposes.

EFFECTS OF Albizia saman PODS SUPPLEMENTATION ON FEED INTAKE AND LIVE WEIGHT CHANGES OF WHITE FULANI CALVES

Nine weaned White Fulani Calves aged between 3 - 13 months, weighing between 28 - 71kg werte fed on ratios consisting of basal Guinea grass hay and 0, 15, 30% Albizia saman replacement for cassava waste in a concentrate ration and each period lasting 28 days feed intake and live weight changes of White Fulani Calves were determined. The DM intake increased with increased level of Albizia saman in the ration, the highest liveweight changes was recorded when the animals were fed 30% Albizia saman whole pod. The result showed that Albizia saman whole pod promotes intake and live weight changes of White Fulani calves, thus can be fed without any adverse effect on calves.