Starchy Waste Research Articles

Availability and saccharification of starchy biowastes for bioethanol production in the Kingdom of Saudi Arabia

AbstractBioenergy has received a great interest because of increase in oil price, rapid depletion of fossil fuels, global climate change, and environmental pollution. However, cheap, and fermentable sugar-rich substrates represent a challenge that face production of biofuel on commercial scale. Therefore, this study offers a reliable solution for sustainability of biofuel production by recycling cheap resource (starchy biowaste) that is abundant in Kingdom of Saudi Arabia (KSA). To achieve the goal of this study, we applied different hydrolysis protocols to obtain a high quantity of fermentable sugars from starchy biowaste collected from restaurants as meal leftover. The results approved that starchy biowastes are abundant in the KSA; with the size of the residue per meal ranging from 149 to 5218 g, and starchy materials, mostly waste rice (WR), representing 72.5%. The saccharification of thermochemically pre-treated WR, carried out using an α-amylase and glucoamylase mixture for 4 h, was the most effective technique amongst all the pre-treatment methods, and produced the highest glucose concentration, i.e. 430.6 g/kg WR. Among five yeast isolates that were tested for their ability to produce ethanol from pre-treated WR via fermentation, Kluyveromyces marxianus KKU-RDI-11 and Pichia kudriavzevii KKU-RDI-18 produced the highest bioethanol concentrations, i.e. 15.44 g/L and 15.62 g/L, respectively. This study recommends application of our technique and the fermentative yeasts on the industrial and commercial scale in KSA, for production of biofuel and recycling of starchy waste materials from restaurants.

Bacterial Nanocellulose‐Based Composite Biocatalysts for Starch‐to‐Bioethanol Valorization under Simultaneous Saccharification and Fermentation

AbstractComposite biocatalysts (CB) consisting of amylases and Saccharomyces cerevisiae immobilized separately on bacterial nanocellulose (BNC) are used for the process of simultaneous saccharification and fermentation (SSF) of starch (5%, w/v) for bioethanol production. Parameters such as: i) addition of phosphates and/or divalent metal‐ions salts during the co‐immobilization process of the amylases, ii) required co‐immobilization time, iii) fermentation temperature and initial pH of starch, and iv) CB as single or double freeze‐dried are studied. The utilization of double freeze‐dried CB exhibits fermentation efficiency 89.9% and ethanol yield 0.51 g ethanol g−1 starch while the single freeze‐dried CB 81.1% and 0.46 g ethanol g−1 starch, respectively. In the case of double freeze‐dried CB, the fermentation efficiency decreases by only 27.1% in two‐recycling batches, while in the single freeze‐dried one decreases by 51.3%. The application of double freeze‐dried CB can be used for: i) the eco‐friendly biosynthesis of value‐added bioproducts; ii) the promising option for fuel‐grade bioethanol through starchy wastes or foodstuff starchy residues treatment, and iii) the implementation of industrialization. Finally, to simulate an industrial process of one‐step SSF of starch by applying a CB model, a technoeconomic analysis is evaluated, where using BNCs makes the bioprocess cost‐effective and environmentally favorable, simultaneously.

Benign-by-design N-doped activated carbon from wasted aqueous assisted hydrochar of leftover rice for efficient H2S removal

The N-doped activated carbon is a potential material for H2S removal, reusing N-rich waste aqueous as a nitrogen source is promising to prepare in-expensive N-doped activated carbon. In this study, N-rich waste aqueous assisted hydrothermal carbonization and KOH activation were used to prepare activated carbon from starchy waste, concentrating on the effects of the nitrogen species (inorganic-N and organic-N) on the physicochemical characteristics and desulfurization performance of carbon material. Introducing inorganic-N (i.e., NH3·H2O) can increase the defect degree and enhance the formation of micropores and mesopores for N-doped activated carbon, leading to high storage ability for desulfurization products and well oxidation performance. The organic-N (i.e., alanine) was conducive to forming pyridinic-N and quinonyl for N-doped activated carbon, resulting in a strong ability of adsorption, dissolution, and oxidation for H2S. The organic-N determined the high breakthrough sulfur capacity for hydrothermal aqueous doping activated carbon (110.7 mg/g), which was ∼ 4.08 times than undoped activated carbon. The primary product of the desulfurization process was elemental sulfur (74.08%), with sulfuric acid and sulfonic acid as the subsequent by-products. After nitrogen doping, the contents of elemental sulfur and sulfuric acid increased by 5.65 and 1.73 times, respectively. The results revealed the correlations between nitrogen species in hydrothermal aqueous and the desulfurization performance of activated carbon, which could guide the selection of nitrogen-rich aqueous for synthesizing H2S removal N-doped activated carbon via the above novel method.

A framework for the design of sustainable multi-input second-generation biorefineries through process simulation: A case study for the valorization of lignocellulosic and starchy waste from the plantain agro-industry

The plantain agro-industry generates different residues in the harvest and post-harvest stages. Therefore, new processes for its valorization are required. The aim of this research was to propose a general methodological framework for the design and analysis of multi-input biorefineries for the valorization of residues with a high content of lignocellulosic and starchy materials. This approach was based on the independent processing of the starchy and lignocellulosic materials in the first steps of the biorefinery and relies on process simulation and hierarchic process design procedures. A case study for the design of a multi-input biorefinery for the valorization of residues from the plantain agro-industry was performed by applying the framework proposed. The biorefinery was simulated using SuperPro Designer software. The results obtained suggest that the best alternative for the valorization of plantain residues under Colombian conditions corresponded to the following distribution of key residues: 100% leaf sheaths processed into the natural fiber production section, and 25% peels and 25% rachis processed into the starch extraction and liquefaction section; with this distribution, an NPV of $21,348,000 can be achieved. This work shows that waste from the plantain agro-industry exhibits high potential as a feedstock for the production of value-added products.

Characterization and potential valorization of industrial food processing wastes

Valorization and utilization of industrial food processing waste as value added products, platform chemicals and biofuels, are needed to improve sustainability and reduce waste management costs. Various industrial food waste stream samples were characterized with respect to their physico-chemical characteristics and elemental composition. A subset of starchy food wastes and milk dust powder were evaluated in batch fermentation to acetone, a useful platform chemical. Production levels were similar to acetone produced from glucose but were achieved more quickly. Lactose concentration negatively affected fermentation and led to 50 % lower acetone concentration from milk dust powder than from starchy wastes. Uncooked starch waste can produce 20 % more acetone than cooked and modified starch waste. Fatty waste and mineral waste can be digested anaerobically generating biogas. Calorific value of soybean waste was 40 MJ/kg sufficiently high for biodiesel production. Low C/N ratios of wastewater and solids from food processing waste makes them unsuitable for anaerobic digestion but these waste types can be converted thermochemically to hydrochar and used as soil amendments. Low calorific content (10–15 MJ/kg) vegetable wastes also are not ideal for energy production, but are rich in flavonoids, antioxidants and pigments which can be extracted as valuable products. A model mapping food waste characteristics to best valorization pathway was developed to guide waste management and future cost and environmental impact analyses. These findings will help advance food industry knowledge and improve sustainable food production through valorized processing waste management.

Growth Media Optimization for Production of Alkaline Protease from Industrial Wastewater using Bacillus subtilis PTCC 1254

Alkaline proteases are widely used in industrial processes due to their high pH tolerance and thermal stability. In present work, the protease producing ability of Bacillus strains (Bacillus subtilis PTCC 1254, B. subtilis PTCC 1156 and B. subtilis PTCC 1715) was studied. B. subtilis PTCC 1254 showed the highest proteolytic activity and therefore, the strain was selected as the biological agent in the submerged fermentation. Cell growth kinetic model was investigated using Malthus and Logistic equations, which were relatively well fitted to the experimental data. The maximum specific growth rate for Malthus and Logistic models were 0.187 and 0.377 h-1, respectively. The optimum culture conditions were defined as follows: pH 9, temperature 37°C, fermentation time 72 h, agitation speed 150 rpm and 4% inoculum with medium contained 1 g/l CaCl2, 0.6 g/l K2HPO4, 1 g/l KH2PO4, 0.2 g/l MgSO4.7H2O, 2 g/l sugarcane bagasse and 4 g/l corn bran as carbon and nitrogen sources. A 25% v/v industrial wastewater containing starchy waste was used as main substrate. Under optimum conditions, maximum alkaline protease activity of 117.43 U/ml was achieved. Also, the obtained protease was able to remove blood stain from cotton fabric and hydrolyze gelatin of X-ray film. Thus, this protease showed potential applications in detergent and photographic industries.

Diversity and activity of amylase-producing bacteria isolated from mangrove soil in Thailand

Abstract. Klinfoong R, Thummakasorn C, Ungwiwatkul S, Boontanom P, Chantarasiri A. 2022. Diversity and activity of amylase-producing bacteria isolated from mangrove soil in Thailand. Biodiversitas 23: 5519-5531. Mangrove forests are a potential ecosystem for the isolation of various economic enzymes derived from mangrove-associated bacteria. The knowledge of amylase-producing bacteria isolated from mangrove forests in the Southeast Asian region has been scarce. This study aimed to investigate the isolation, genetic identification, and activity characterization of amylase-producing bacteria from mangrove soils in Thailand. The amylase-producing bacteria isolated from mangrove soils in the present were genetically belong to the genera Bacillus, Desulfurella, Peribacillus, Priestia, and Pseudomonas. Several amylase-producing bacteria such as Bacillus proteolyticus, Desulfurella, Pseudomonas entomophila, and Pseudomonas putida found in this study have hardly ever been reported. The Bacillus paralicheniformis strain DNP0507 was the most active amylolytic bacterium with 2.395 ± 0.133 U/mg of amylase activity. The optimum temperature and pH for amylolytic activity were determined to be 50°C at a pH of 7.0 with a thermal stability range of 20-60°C at a neutral pH of 7.0-8.0. The enzyme activity was significantly enhanced by Cu2+, Co2+, and Pb2+ and was inhibited considerably by a chelating agent EDTA. Finally, the most active amylolytic B. paralicheniformis strain DNP0507 could be applied in baking industries, food industries, and starchy waste valorization.

Towards a Biorefinery Processing Waste from Plantain Agro-Industry: Process Design and Techno-Economic Assessment of Single-Cell Protein, Natural Fibers, and Biomethane Production through Process Simulation

The plantain agro-industry generates different residues in the harvest and post-harvest stages. Therefore, the design of processes for valorization is required. The aim of this work was to design and techno-economically evaluate the processes for the production of single-cell protein, natural fibers, and biomethane from plantain residues by process simulation in the framework of the design of a future biorefinery for valorization of these residues. The processes were simulated using SuperPro Designer. The scale size was calculated at 1,267,071 tons for the processing of plantain lignocellulosic waste (pseudostems) and 3179 tons for the processing of starchy waste (rejected unripe plantain fruits). The results obtained suggest that the best alternative for the valorization of plantain residues corresponded to the production of natural fibers, with a net present value of $29,299,000. This work shows that waste from the plantain agro-industry exhibits high potential as a feedstock for the production of value-added products. In addition, the process flowsheets simulated in this work can be integrated into the basic design of a biorefinery processing plantain waste.

Engineering Cupriavidus necator DSM 545 for the one-step conversion of starchy waste into polyhydroxyalkanoates

Starch-rich by-products could be efficiently exploited for polyhydroxyalkanoates (PHAs) production. Unfortunately, Cupriavidus necator DSM 545, one of the most efficient PHAs producers, is not able to grow on starch. In this study, a recombinant amylolytic strain of C. necator DSM 545 was developed for the one-step PHAs production from starchy residues, such as broken rice and purple sweet potato waste. The glucodextranase G1d from Arthrobacter globiformis I42 and the α-amylase amyZ from Zunongwangia profunda SM-A87 were co-expressed into C. necator DSM 545. The recombinant C. necator DSM 545 #11, selected for its promising hydrolytic activity, produced high biomass levels with noteworthy PHAs titers: 5.78 and 3.65 g/L from broken rice and purple sweet potato waste, respectively. This is the first report on the engineering of C. necator DSM 545 for efficient amylase production and paves the way to the one-step conversion of starchy waste into PHAs.

Consolidated bioprocessing of starch based on a bilayer cell factory without genetic modification of yeast

The exploitation of starchy wastes for the production of value-added products and the consolidated bioprocessing (CBP) have a positive environmental and cost-effective impact. For this reason, a cell factory (CF) was employed to perform three bioprocesses in one step (CBP) for alcoholic fermentation of starch without genetic modification. CF is a bilayer biocatalyst consisting of an inner layer of immobilized Saccharomyces cerevisiae on tubular cellulose (TC) and an external layer of immobilized Aspergillus awamori on alginates (ALG). In first, the suggested CF was proved to be more effective compared with co-immobilized S. cerevisiae and A. awamori on ALG beads for starch fermentation. Subsequently, the effect of the (i) S. cerevisiae concentration (g S. cerevisiae/g TC) during its immobilization, (ii) CaCl 2 concentration (% w/v), (iii) form of bilayer CF (wet or freeze-dried) and (iv) freeze-dried CF concentration on 5% (w/v) starch fermentation was examined. It was found that the higher ethanol production (32.17 mL/L), productivity (4.60 mL/L/d) and yield (0.51 g ethanol/g starch) reaching the theoretical one were obtained when the CF in freeze dried form fermented 100 mL of 5% (w/v) starch solution. Finally, two repeated fermentation batches were performed using the best CF. The ethanol yield was decreased during the repeated fermentation batches, but remained in acceptable levels. The successful preparation of CF was verified with FTIR spectroscopy, SEM and TEM analysis. The results indicated that the objective of designing CF was successfully achieved, and the results are promising to be the base for the exploitation of starchy wastes and the development of an innovation in brewing industry by eliminating the malting stage. This CF can be applied as model for different bioprocesses of White Biotechnology, e.g. substituting S. cerevisiae with the appropriate microorganism to produce other metabolites of added value.

Molecular biohydrogen production by dark and photo fermentation from wastes containing starch: recent advancement and future perspective.

Changing lifestyle is increasing the energy demand. Fossil fuel is unable to deliver such huge energy. Clean energy from renewable source can solve this problem. Hydrogen is a clean and energy-efficient fuel and used for electricity generation by fuel cells or can be used in combustion engine. Easy availability of starch wastes from different industrial food processing wastes makes it a potential source for hydrogen (H2) generation. Among various processes such as steam reforming, electrolysis, biophotolysis of water and anaerobic fermentation, anaerobic fermentation technique is environmentally friendly and requires less external energy, making it a preferred process for H2 generation. Dark fermentation process can use wide range of substrates including agricultural and industrial starchy waste with low level of undesirable compounds. Application of both anaerobic dark and photofermentation can improve H2 yield and production rate. H2 production from wastes containing starch serves dual benefit of waste reduction and energy generation. As starch is a polymer and all hydrogen-producing bacteria cannot produce amylase to hydrolyze it, a pretreatment step is required to convert starch into glucose and maltose. In this present review paper, we have summarized: (i) potential of various types of starch-containing wastes as feedstock, (ii) various fermentation techniques, (iii) optimization of external process parameter, (iv) application of bioreactor and simulation in fermentation technique and (v) advancement in H2 production from starchy wastes.

Optimization of dark fermentation for biohydrogen production using a hybrid artificial neural network (ANN) and response surface methodology (RSM) approach

AbstractHerein, the production of biohydrogen by dark fermentation was optimized using a novel hybrid approach that combines ANNs (artificial neural networks) with RSM (response surface methodology). Using the limited numbers of data (15 runs) as training data set together with one cross‐out method for validation, the complete 29 runs of well‐established data matrix were created from ANNs for RSM statistical analysis in order to correlated the critical process parameters with hydrogen production performance. This methodology was found to be robust, cost‐effective, reliable, and can be extensively analyzed the critical operational parameters, that is, carbon sources (obtained from potato peel wastes and starchy wastes), metal cofactor Fe0, pH, and dose levels of microbes on the hydrogen production, along with concentrations of other metabolites, such as acetic acid, propionic acid, butyric acid, valeric acid, and ethanol. The established ANNs‐RSM model using Box–Behnken design indicates the significant changes caused by the variations of a few critical operation parameters. The resultant model shows an exceptionally good result in terms of nonlinear noisy processes. Both single and multiple objective optimizations for dark hydrogen fermentation can achieve by using the established hybrid ANN‐RSM system. The optimal operating conditions (starch 6.2 kg/m3, pH 6.7, Fe0 11.7 g/m3, sludge 24.6 g/m3) could lead to the generation of hydrogen with a yield of 106.2 (cm3/g) and metabolites, that is, propionic acid (2.8 kg/m3), butyric acid (2E−2 kg/m3), valeric acid (4E−4 kg/m3) acetic acid (1.9 kg/m3), and ethanol (0.1 kg/m3) simultaneously.

Conversion of Starchy Waste Streams into Polyhydroxyalkanoates Using Cupriavidus necator DSM 545.

Due to oil shortage and environmental problems, synthetic plastics have to be replaced by different biodegradable materials. A promising alternative could be polyhydroxyalkanoates (PHAs), and the low-cost abundant agricultural starchy by-products could be usefully converted into PHAs by properly selected and/or developed microbes. Among the widely available starchy waste streams, a variety of residues have been explored as substrates, such as broken, discolored, unripe rice and white or purple sweet potato waste. Cupriavidus necator DSM 545, a well-known producer of PHAs, was adopted in a simultaneous saccharification and fermentation (SSF) process through an optimized dosage of the commercial amylases cocktail STARGEN™ 002. Broken rice was found to be the most promising carbon source with PHAs levels of up to 5.18 g/L. This research demonstrates that rice and sweet potato waste are low-cost feedstocks for PHAs production, paving the way for the processing of other starchy materials into bioplastics.

Bioethanol production from cassava-based industrial wastes using acid hydrolysis and simple fermentation

Tapioca flour industry produces starchy wastes. Improper handling of this waste can cause environmental problems. The bioconversion of starchy waste to bioethanol has been widely performed. However, the utilization of solid waste from the tapioca flour industry for bioethanol production is still limited. This research is a preliminary investigation to determine the level of ethanol produced from cassava pulp and peel by the fermentation process. Cassava pulp and peel were prepared for the delignification process, hydrolysis process, fermentation process, and finally, the purification process. The fermentation process was carried out by varying fermentation periods, i.e., 2, 4, 6, 8, 10, 12, and 14 days. The highest ethanol concentration at 6.2% was obtained after eight days of fermentation.

Utilizing Gelatinized Starchy Waste from Rice Noodle Factory as Substrate for L(+)-Lactic Acid Production by Amylolytic Lactic Acid Bacterium Enterococcus faecium K-1.

To valorize starchy waste from rice noodle factory, bioconversion of gelatinized starchy waste (GSW) to value-added product as L(+)-lactic acid, the monomer for polylactate synthesis, was investigated using amylolytic lactic acid bacterium, Enterococcus faecium K-1. Screening for appropriate nitrogen source to replace expensive organic nitrogen sources revealed that corn steep liquor (CSL) was the most suitable regarding high efficacy for L(+)-LA achievement and low-cost property. The successful applying statistic experimental design, Plackett-Burman design incorporated with central composite design (CCD), predicted the maximum L(+)-LA of 93.07g/L from the optimized medium (OM) containing 125.7g/L GSW and 207.3g/L CSL supplemented with CH3COONa, MgSO4, MnSO4, K2HPO4, CaCl2, (NH4)2HC6H5O7, and Tween80. Minimizing the medium cost by removal of all inorganic salts and Tween80 from OM was not an effect on L(+)-LA yield. Fermentation using the optimized medium without minerals (OM-Mi) containing only GSW (125.7g/L) and CSL (207.3g/L) in a 10-L fermenter was also successful. Thinning GSW with α-amylase from Lactobacillus plantarum S21 increased L(+)-LA productivity in the early stage of 24-h fermentation. Not only showing the feasible bioconversion process for GSW utilizing as a substrate for L(+)-LA production, this research also demonstrated the efficient model for industrial starchy waste valorization.

Using starchy waste as a promising raw material for bioethanol production with consequence purification using chitosan/sodium alginate polymeric membrane

Using starchy waste as a promising raw material for bioethanol production with consequence purification using chitosan/sodium alginate polymeric membrane

Simultaneous Bioconversion of Gelatinized Starchy Waste from the Rice Noodle Manufacturing Process to Lactic Acid and Maltose-Forming α-Amylase by Lactobacillus plantarum S21, Using a Low-Cost Medium

A direct bioconversion of gelatinized starchy waste (GSW) to lactic acid by amylolytic lactic acid bacterium Lactobacillus plantarum S21 was investigated. Corn steep liquor (CSL) was selected as the most suitable low-cost nitrogen source for replacing yeast extract, beef extract, and peptone in De Man, Rogosa and Sharpe (MRS) medium. Plackett–Burman design results indicated that GSW and CSL were the two most nutrients that significantly influence lactic acid production, among eight medium components, including GSW, CSL, K2HPO4, CH3COONa, (NH4)2HC6H5O7, MgSO4, MnSO4, and Tween 80. A new low-cost medium containing only GSW (134.4 g/L) and CSL (187.7 g/L) was achieved as omitting other six components from the optimized medium had no effect on lactic acid yield. Batch fermentation at 37 °C both in 1 L and 10 L jar fermenters showed non-significantly different productivity. A by-product, maltose-forming α-amylase, was successfully achieved up to 96% recovery yield using an ultrafiltration unit equipped with a 50 kDa cut-off membrane. Crude lactic acid exhibited the additional benefit of antimicrobial activity against food and feed pathogens Salmonella enterica serovar Typhimurium TISTR 292, Vibrio cholerae TH-001, and also E. coli ATCC 25922. This study presents a promising bioprocess for the simultaneous production of lactic acid, and a value-added food enzyme, using only two industrial wastes, GSW and CSL, as the medium components.

Novel Yeast Strains for the Efficient Saccharification and Fermentation of Starchy By-Products to Bioethanol

The use of solid starchy waste streams to produce value-added products, such as fuel ethanol, is a priority for the global bio-based economy. Despite technological advances, bioethanol production from starch is still not economically competitive. Large cost-savings can be achieved through process integration (consolidated bioprocessing, CBP) and new amylolytic microbes that are able to directly convert starchy biomass into fuel in a single bioreactor. Firstly, CBP technology requires efficient fermenting yeast strains to be engineered for amylase(s) production. This study addressed the selection of superior yeast strains with high fermentative performances to be used as recipient for future CBP engineering of fungal amylases. Twenty-one newly isolated wild-type Saccharomyces cerevisiae strains were screened at 30 °C in a simultaneous saccharification and fermentation (SSF) set up using starchy substrates at high loading (20% w/v) and the commercial amylases cocktail STARGEN™ 002. The industrial yeast Ethanol Red™ was used as benchmark. A cluster of strains produced ethanol levels (up to 118 g/L) significantly higher than those of Ethanol Red™ (about 109 g/L). In particular, S. cerevisiae L20, selected for a scale-up process into a 1-L bioreactor, confirmed the outstanding performance over the industrial benchmark, producing nearly 101 g/L ethanol instead of 94 g/L. As a result, this strain can be a promising CBP host for heterologous expression of fungal amylases towards the design of novel and efficient starch-to-ethanol routes.

Enhanced Bioethanol Production from Potato Peel Waste Via Consolidated Bioprocessing with Statistically Optimized Medium.

In this study, an extensive screening was undertaken to isolate some amylolytic microorganisms capable of producing bioethanol from starchy biomass through Consolidated Bioprocessing (CBP). A total of 28 amylolytic microorganisms were isolated, from which 5 isolates were selected based on high α-amylase and glucoamylase activities and identified as Candida wangnamkhiaoensis, Hyphopichia pseudoburtonii (2 isolates), Wickerhamia sp., and Streptomyces drozdowiczii based on 26S rDNA and 16S rDNA sequencing. Wickerhamia sp. showed the highest ethanol production (30.4g/L) with fermentation yield of 0.3g ethanol/g starch. Then, a low cost starchy waste, potato peel waste (PPW) was used as a carbon source to produce ethanol by Wickerhamia sp. Finally, in order to obtain maximum ethanol production from PPW, a fermentation medium was statistically designed. The effect of various medium ingredients was evaluated initially by Plackett-Burman design (PBD), where malt extracts, tryptone, and KH2PO4 showed significantly positive effect (p value <0.05). Using Response Surface Modeling (RSM), 40g/L (dry basis) PPW and 25g/L malt extract were found optimum and yielded 21.7g/L ethanol. This study strongly suggests Wickerhamia sp. as a promising candidate for bioethanol production from starchy biomass, in particular, PPW through CBP.

Bioprospecting microbes for single-cell oil production from starchy wastes

ABSTRACTProduction of lipid from oleaginous yeast using starch as a carbon source is not a common practice; therefore, the purpose of this investigation was to explore the capability of starch assimilating microbes to produce oil, which was determined in terms of biomass weight, productivity, and lipid yield. Saccharomyces pastorianus, Rhodotorula mucilaginosa, Rhodotorula glutinis, and fungal isolate Ganoderma wiiroense were screened for the key parameters. The optimization was also performed by one-factor-at-a-time approach. Considering the specific yield of lipid and cell dry weight yield, R. glutinis and R. mucilaginosa showed superiority over other strains. G. wiiroense, a new isolate, would also be a promising strain for starch waste utilization in terms of extracellular and intracellular specific yield of lipids. Extracellular specific yield of lipid was highest in R. glutinis culture (0.025 g g−1 of biomass) followed by R. mucilaginosa (0.022 g g−1 of biomass) and G. wiiroense (0.020 g g−1 of biomass). Intracellular lipid was again highest in R. glutinis (0.048 g g−1 of biomass). The most prominent fatty acid methyl esters among the lipid as detected by GC-MS were saturated lipids mainly octadecanoic acid, tetradecanoate, and hexadecanoate. Extracellular lipid produced on starch substrate waste would be a cost-effective alternative for energy-intensive extraction process in biodiesel industry.