Enhanced Production of Citric Acid by Mutant PN12 of Aspergillus fumigatus Using Statistical Design

Distillery spent wash is an unwanted residual liquid waste generated during alcohol production. It is a potential source for production of different industrially important products. Distillery spent wash is dark colored and has many organic compounds as a waste. In this experiment, removal of color and organic compounds was carried out by anaerobic treatment. The treated spent wash was utilized for citric acid production with the help of microorganisms. The current study was performed with the treated spent wash which was applied for high level of citric acid production by a mutant strain of Aspergillus fumigatus PN12. The parent strain Aspergillus fumigatus PN12 was mutagenized by UV exposure to enhance citric acid production. After UV exposure investigation, mutant strain was selected for optimization and statistical method. The best citric acid production obtained was, 26.45 g/L at 30 ℃ with pH 6.0, 0.1 g/L of KH2PO4 and (NH4)2SO4 under OFAT. Under RSM optimization, maximum citric acid production was achieved as 30.89 g/L. Thus, the process optimization through the statistical approach resulted in a 1.16-fold enhancement in citric acid production as compared to that of the OFAT parametric conditions. Citric acid producing enzymes such as aconitase, NAD+-isocitrate dehydrogenase and NADP+ isocitrate dehydrogenase was studied. Maximum activity (U/mg) of aconitase (3.19±0.023), NAD+-isocitrate dehydrogenase (3.0±0.15) and NADP+ isocitrate dehydrogenase (2.91±0.17) was observed at 96 h. The present study can conclude that spent wash is potential source for citric acid production. Utilization of mutant strain of Aspergillus fumigatus PN12 is beneficiary for large scale industrial fermentation and citric acid production.

Analysis of the Physicochemical Characteristics of Distillery Wastewater at Habib Sugar Mills, Nawabshah

The aim of this study is to perceive the level of significant physicochemical characteristics of Distillery Wastewater (DWW) at Habib Sugar Mills, Nawabshah, Pakistan. Five locations in the mill namely spent wash, digester tank, distillery, primary treatment, and secondary treatment were selected for analysis of pH, Total Dissolved Solids (TDS), Total Suspended Solids (TSS), and Chemical Oxygen Demand (COD) of the samples. The samples were taken on a weekly basis for four succeeding months, from January 2021 to April 2021 and the experiments were carried out in the laboratory by adopting standard procedures. The results revealed that the pH of the samples from spent wash was the lowest, whereas secondary treatment samples had the highest. On the contrary, the highest concentrations of TDS, TSS, and COD were found in the samples taken from the spent wash and the lowest from the secondary treatment. The pH values were found abruptly increasing in the digester tank due to the addition of calcium carbonate in the stream of wastewater after the spent wash. The COD concentration was found to rapidly decrease, from more than 106000mg/l in the spent wash to around 35000mg/l in the digester tank samples, and then to gradually decrease up to the final point of disposal. Overall, TDS, TSS, and COD values were higher during April, January, and February and lower during March. The level of pH was extremely low in the spent wash and did not meet the lower limits of standards and the other examined parameters exceeded the upper limits of WHO standards.

​Effect of Distillery Spent Wash as Carbon Source in Biofloc System on Nutrient Profile of GIFT Tilapia

Background: Biofloc technology (BFT) is an ecofriendly aquaculture production system. In this, various carbon sources being used for floc production. However, the cheapest carbon source would make it economically feasible. In this context, the present study used purified distillery spent wash (DSW) as a carbon source to evaluate its viability on biofloc composition and carcass quality of GIFT strain. Methods: Nursery trial was conducted in high density poly ethylene (HDPE) outdoor lined pond (0.01 ha) for period of 30 days (8th January to 7th February 2018). In both BFT and control system, proximate composition and fatty acid profile of GIFT tilapia were analyzed at the end of the trial by following the standard method. Result: Dried microbial floc encompassed 16.61 ± 1.2% of crude protein and 15.3 ± 0.01% of linoleic acid. The Whole-body composition of GIFT was not significantly (P greater than 0.05) varied in between biofloc and control. Significantly (P less than 0.05) rich fatty acids found in biofloc fed GIFT whole body except stearic acid, behenic acid and docosahexaenoic acid. In the present study, DSW did not show much effect on carcass quality but showed better growth performance of GIFT strain in the BFT system.

Degradation of distillery spent wash using monopolar parallel and monopolar series electrocoagulation process

In waste treatment and water management issues, electrocoagulation (EC) is the most cost-effective and environmentally friendly option. In the study, EC treatment of distillery spent wash was carried out using new electrodes packed with aluminium foil scraps. These metal scraps were packed in a mesh to function as anode and cathode electrodes. Electrochemical treatment was carried out for 150 minutes, and samples were analysed regularly to determine the colour and chemical oxygen demand (COD). The impact of operating parameters such as pH, applied current, electrolysis time, agitation speed, and electrode distance on colour and COD removal was investigated. The EC processes were carried out in monopolar parallel (MP-P) and monopolar series (MP-S). The MP-S connection measured the potential difference between the amplified pair of electrodes, whereas the output signals in the MP-P connection were formed by several input electrodes, resulting in a high removal rate. The results indicated that the MP-P relationships enhance the COD removal rate by 4.16 to 8.06 %. An optimum chemical oxygen demand degradation is 77.29 % at pH 3, and decolourisation is 76.55 % at pH 8.3. TDS is reduced to a maximum of 58.32 %, while sulfate and chloride are reduced to 64.72 and 20.44 %, respectively.