The production of citric acid, a vital agricultural commodity utilized across various industries such as food, beverages, pharmaceuticals, agriculture, detergents, and cosmetics, predominantly relies on microbial fermentation, with Aspergillus niger accounting for approximately 90% of global production. In this study, we aimed to optimize the key factors influencing citric acid production, with a focus on strains, fermentation techniques, and carbon sources, particularly sugarcane molasses. A. niger, sourced from the Botany department/Biotechnology laboratories at Govt. College of Science, Lahore, was employed for citric acid production. The process involved inoculum preparation through spore collection from 3 to 5 days of cultured PDA slants. The fermentation medium, comprising cane molasses with a 15% sugar concentration, was meticulously prepared and optimized for various factors, including magnesium sulfate, potassium ferrocyanide, time of addition of potassium ferrocyanide, ammonium oxalate, and calcium chloride. Our optimization results shed light on the significant impact of different factors on citric acid production. For instance, the addition of 0.4 g/L magnesium sulfate led to a maximum yield of 75%, while 2 g/L potassium ferrocyanide, added at 24 h, achieved a yield of 78%. Remarkably, ammonium oxalate, at a concentration of 10 g/L, resulted in a notable 77% yield. Conversely, the addition of calcium chloride exhibited negligible effects on citric acid production, with the control group yielding more at 78%. Our study underscores the potential for optimizing factors to enhance citric acid production by A. niger in submerged fermentation. These findings highlight the pivotal role of magnesium sulfate, potassium ferrocyanide, and ammonium oxalate in augmenting citric acid yields while emphasizing the minimal impact of calcium chloride. Ultimately, these insights contribute to advancing our understanding of microbial citric acid biosynthesis, providing valuable implications for industrial applications and future research endeavors.

The genus Trichoderma holds economic significance due to its widespread distribution and diverse applications, including biological control, enzyme production, and various biotechnological uses. The accurate identification of Trichoderma species is crucial given their close association with human activities. Despite previous efforts in classification, a comprehensive analysis combining morphological and molecular approaches is necessary. This study focuses on the isolation of four Trichoderma species from industrial wastewater in Pakistan, expanding on the known diversity in the region; isolation involved collecting samples from industrial wastewater effluents at specific sites in Punjab, Pakistan. Trichoderma strains were cultured and purified on solid media, with subsequent biomass production for bisorptional activity. Morphological characterization included colony features and microscopic examinations. DNA extraction, polymerase chain reaction (PCR), and sequencing of the internal transcribed spacer (ITS) region were conducted for molecular analysis. Phylogenetic analysis was performed using the Maximum Likelihood Algorithm. The study identified three Trichoderma species, viz. T. citrinoviride, T. erinaceum, and T. longibrachiatum. Each species was characterized morphologically and supported by molecular–phylogenetic analysis. Illustrations of microscopic features and a phylogenetic tree based on the ITS-nrDNA region were recorded. T. citrinoviride and T. longibrachiatum, isolated from steel mill and tanneries wastewater, respectively, were differentiated based on morphological characteristics such as phialides and conidia. The combination of morphological and molecular techniques enhances the accuracy of species identification. The study highlights the significance of Trichoderma in industrial wastewater environments and underscores the need for continued research in this area. Future research should focus on exploring the ecological roles and potential applications of the newly identified Trichoderma species. Additionally, further investigations into the biotechnological potential of these species, including enzyme production and bioremediation capabilities, would contribute to their practical applications.

Ensuring access to clean and safe drinking water is a critical component of a healthy lifestyle. In this study, we report the development of a novel eco-friendly polyvinyl alcohol (PVA)/iron oxide nano-membrane synthesized using a green method for iron oxide nanoparticle production. This work is distinctive in its integration of green-synthesized iron oxide nanoparticles into a flexible, reusable PVA matrix, forming a next-generation membrane with multifunctional water purification capabilities. The nanoparticles, with an average size of 10 ± 9 d.nm, were characterized using SEM, nano zeta sizer, FTIR, and UV–Vis spectroscopy, confirming their nanoscale morphology and functional properties. The fabricated nano-membrane was evaluated for its efficacy in treating drinking water samples from diverse geographic regions of Wah Cantt, Attock, and Taxila, Pakistan, making this one of the few studies to test real-world water samples using green nano-membranes. Results indicated that nano-membrane acts as a highly effective disinfectant against microbes, turbidity decreased by 88.8%, from 40 NTU to 4.48 NTU, sodium content reduced by 28%, from 43 mg/L to 31 mg/L, total hardness decreased by 9.4%, from 519 mg/L to 470 mg/L, nitrate levels dropped by 63.5%, from 49.9 ppm to 18.2 ppm, and pH decreased slightly by 2.6%, from 7.28 to 7.09. This study introduces a sustainable, cost-effective, and scalable approach to membrane-based water purification, providing a valuable framework for the design of future nano-enabled filtration systems. The novelty lies not only in the green synthesis and practical application of the nano-membrane, but also in its demonstrated real-world performance across varied water sources, making it a promising candidate for widespread deployment in resource-limited settings.

Agricultural waste (crop residues and animal manure) is a significant byproduct of farming activities. It holds potential for sustainable agriculture, renewable energy production, and environmental conservation. However, traditional disposal challenges persist, leading to air pollution and soil degradation. Innovative approaches include converting agricultural waste into bioenergy like bioethanol and biogas and producing biochar from agricultural residues, which improves soil health, water retention, and nutrient availability while sequestering carbon. Agricultural waste is also finding applications in industries. Integrating agricultural residues into industrial processes not only adds value to waste but also reduces reliance on raw materials like fossil fuels and wood. In livestock farming, crop residues are critical as feed and bedding, particularly in resource-constrained regions. While their nutritional content is often low, treatment methods can improve their digestibility. By integrating cutting-edge technologies and supportive policies, it is possible to transform agricultural waste from a burden into a resource, paving the way for a more sustainable agricultural future.

This chapter aims to explore the latest advancements in biodiesel plant technologies and their implications for sustainable development. It will delve into the various stages of biodiesel production, from feedstock selection to processing techniques, highlighting innovations that enhance efficiency and reduce environmental impact. The chapter will also examine the role of biodiesel in the broader context of renewable energy, addressing challenges and opportunities for scaling up production. By analyzing case studies and industry trends, the chapter will provide insights into the future trajectory of biodiesel plants and their significance in mitigating climate change while promoting energy independence and sustainable development.